The short of it:
I very much agree with @Wasnex said, get two 8Ω 210 cabs. Use one for small and medium-sized venues and both of them large venues and outdoors. It's a very modular solution that lets you bring what you need to the gig without hauling around more of being told by a venue, not to bring in your 410. However, the trick is to make sure you get 210 cabs that can handle the power.
The Long of it:
That Little Mark Tube 800 will put out 500-watts into 8Ω and 800-watts rms into 4Ω. So you're going to need to look for 210-cabs that can handle 500-watts rms each. You can get by with using cabs that handle less than that as long as you don't crank them and you listen to your sound to make sure you are not getting distortion caused by the speakers and not the tube. Honestly if you run distortion from your amp anyhow and you crank the master on the one cab, odds are you will blow the cab before you realized it is stressed. So if you are running a clean signal, not cranking the master, and keep your bass EQ reasonably close to flat, using a single cab with 400-watts handling power will work. A 210 cab with 300-watts rms handling power really won't. It's just too easy to nudge the sound up higher than is safe with that much disparity - one accidental bump of the master could blow the speakers.
Both of them together should work fine with that amp because it would split the 800-watts out to 400-watts per cab (using two 8Ω cabs). With Markbass that means your options are either of the MB58R 102 XL PURE or their MB58R 102 XL ENERGY. Both of those will handle 400-watts rms. Getting a single 410 cab that will handle 800-watts is easier, but not if the venue doesn't allow you to bring a 410 into their venue...been there, done that.
I can tell you a couple of things that I regret doing. I bought a DNS-410 cab back in 2015. It will handle 1400-watts rms and has a max SPL rating of 137db. I figured it would replace my old 410+115 stack and I should never have to buy another cab again. Well that DNS-410 did not disappoint. Amazingly clear, clean, articulate sound with a tightly focused bottom end and it is LOUD! Thought I'd died and gone to heaven. It arrived 2-days before I moved from Virginia to Washington state.
I ended up joining two groups in Washington and one of them hosted a 7PM to 10PM Open Mic Night at a small local brewpub almost every Friday night (over 40 Friday nights a year). I rolled my 410 in and then had to roll it back out again. It about gave the owner apoplexy. Said it was way too much for his brewpub and insisted I use his Peavey 112 combo instead. Never considered my cab might be too much for somewhere. "You know I do have a master volume control on my amp and it still sounds good turned down." He was having none of that and I got stuck with the Peavey 112 combo that I just couldn't get a good sound out of. In any case there are over 400 brewpubs in Washington and a lot of them are small venues who have the same reaction when I try to bring in my 410. So size matters and needs to match the venue.
In 2019 when I got my DNA Endorsement, I bought the DNS-210. It handles 700-watts, has a max SPL of 134db and nobody ever looks twice at a bass player bringing in a 210. It has all the same sonic characteristics to its sound as the 410 but goes a little lower, reproducing the fundamentals down to 34Hz (DNS-410 goes down the 37db). Since it was rated at 700-watts power handling, I went ahead and used my 800-watt Eden WT500/800 amp bridged at 800-watts into it. That cab is so loud I've never run the master of my big Eden amp higher than 10:30 with it. And that's more than enough to fill a large venue. I've ended up using it for all my indoor venues now and just reserve my 410 for outdoor venues and Music Festivals.
Point is that I should have purchased the 210 first and then later, when I needed it, bought the second DNS-210 cab. That way I could take the 210 to most of my gigs but add a second one to use as needed outdoors. The DNS-210 is in a big box and it weighs 52-lbs. That's lighter than the Eden 210 cabs that David designed for Eden, but there are lighter ones out there. HOWEVER, there are very few 210 cabs that can handle 700-watts with enough sensitivity to fill a large indoor venue and that 52-lbs is considerably lighter than my DNS-410.
At wide-open music festivals I use my 410 but if I turn the master on my Eden amp up to 10:30, I always get told by the sound crew to turn down. So I pull it down to 10:15 and that seems to mollify them while still keeping me happy. I've no doubt I would get the same result using 2x210 cabs instead of the one 410. Good news is that I never need to get an 810 cab and lug that around. Bad news is that although I have both the 410 and 210, there's really no reason to ever stack them and run both at once. It does really look good though. I stacked them the first time I tried playing a large venue with the 210 so I could unplug the 210 and plug in the 410 if needed. The DNS-210 though more than handled it, so I just ran the 210 all night and used my DNS 410 as a very expensive amp stand. As you can see below, the stack did look good though!
View attachment 7172567
Before I bought that DNS-210 though, I looked for an Eden 112 combo. They didn't have one when I was looking but I could buy an Eden EX-112 cab for just $265. Eden's top of the line D112XST cab on the other hand is a good $600 more. I have a friend in the UK who has been using his EX-112 cabs for years and loves them, so I decided to take a chance and order one. Since I figured I'd only ever use one, I went ahead and got the 4Ω version instead of the 8Ω. That was my second mistake.
The first night I played through that EX-112 cab, I was amazed at how good it sounds. So good in fact that I ordered a second one the next day so I could use two of them at our medium-sized venues. Those cabs are really compact because they don't have a separate tweeter horn. Instead it has a whizzer cone which is a second cone inside the woofer cone. That arrangement was why I was originally hesitant about the cab. Often hi-mids and highs are weak and fragile with that type of cone. But that wasn't a problem with these cabs at all. They do sound great and I got a lot of compliments over the year+ that I used them.
The cabs use Neo speakers and each cab weighs 30-lbs. But, because I bought them as 4Ω cabs, the only amp I had that will handle both of them was my big Eden cab. It puts out 400-watts into 4Ω per channel. Their handling power is 300-watts rms, so I knew I'd have to be careful not to crank the amp when driving them. I usually played medium-sized venues with my master around 9:30 or 10 o'clock though, so I've never stressed them. Even though my stack looked like a giant "T" with my WT500/800 hanging over the edge of the speakers, it really sounds good and I received a lot of complements over the time I used them. If I had bought the first in 8Ω and then the second also in 8Ω, I could have used my 400-watt into 4Ω Eden amp to drive the two of them without the worry of stressing the speakers.
View attachment 7172578
Until 2019, I used one EX-112 cab in small-venues and two in medium-sized venues. Although I no longer use both of those 112's, I still do use one of them for small venues and drive it with an Eden class D TN-226 (225-watts rms). That's a great sound and a very light setup. I put the 4.7-lb. amp in its shoulder bag over one shoulder, my gig bag over the other shoulder, grab the cab by it's handle (top back center) in one hand and my bass in its case in the other and move everything in or out one trip. And to top it off, everything fits just fine in a chair without overhanging the edges.
View attachment 7172591
And, of course, if I had purchased these 2 cabs in 8Ω I would have opted for the Eden 500-watt into 4Ω class D TN-501 (5.3-lbs) instead of the lower power TN-226 (225-watts into 4Ω). That would not only have looked better than using my heavy WT500/800 (37½-lbs in its rack). Yes indeed, hindsight is a great thing.
