Quickie Survey

Why would you want the 212 and a 15? You won't really get more bass out of it and the 15 will be working twice as hard as the 212. If you are still searching for your dub sound I would suggest checking out the Peavey PVH 212. Made for drop tuning and they can do some serious low end thump. I have a pair and a 1000 watt head and they make some lows with out becoming overly muddy. And if you are trying to squeeze out every last watt from that head by using the 212 and 115 it is not really worth doing that way. The preferred way would be a second Identical 212 or a pair of 115's

 

Also it would help some if you said what results you were looking for .

 

PR 2x12 unless weight is not an issue then try each
Acoustic 370 is not that loud at 8 ohms; how loud do you need

 

I don't know those cabs never used them or heard them . A lot of times swapping speakers is a crapshoot. And even if they work to a point if the cab is too big or small it can limit low end response or power Handling and the speakers will fail. So if you do put them in there use caution with power until you find out how they respond . You don't want to toast those speakers. And I agree the 212 over a 115 but if you have 2 115';s then either direction

 

I had one for years and used it with a highly effecient cabinet.
People remember them as much more powerful than the are.
At 3.2 Ohms, 5% distortion, 205 watts.
http://mikesgig.com/wp-content/uploads/2013/11/Acoustic-370-manual-410056.pdf

 

There are 3 different SVT 410 HLF iterations. The Classic 410 HLF mud and boom cabs the new Heritage 410hlf and the Newer Classic 410Hlf that still has great bottom but is much cleaner and more defined. I have the latter one and it is a great cab . Running it with a 300 watt Fender Super Bassman all tube Head.