My Reggae band is dormant for now, unfortunately, but a day doesn't go by that I don't play some reggae bass at home or much less often in a jam situation. I also host a regular Sound System at a large bar here, and we get 200-300 each time for a great night with me selecting, toasting, and sometimes hosting guest DJs like Echo Minott from JA and various Swiss toasters.
My reggae bass is a CS Fender '64 Jazz, with old Sadowsky flats. When I was gigging I had very old Labella FL760 flats on her, and will pop those beauties back on when I get the band together again next autumn. The Sadowskys are a hair lacking in thump and a drop too aggressive compared to the LaBellas, but I would be happy using them instead anyway. I roll off the bridge PUP halfway for that special fattening it gives the tone from the bass, and roll off the treble a third at most.
My rig is an old SVT through a Berg NV610 and an NV215, whether through the PA or not. I used to lack a bit tonewise through a PA as I didn't use any outboard EQ, but since I got a VT Character pedal I know I'm sorted for the future. This pedal gives me the same effect through a PA as I get through my live rig when the SVT is set around its breakup point, with gobs of tube thickness and no lack of punch. When you crank the lows on this pedal, they just get bigger and fatter without adding any mud, really perfect for reggae, IMO.
I go for a real old school tone, preferring the passive bass with tube colouring to the more produced and heavily EQed tones more common these days; I find I can play more expressively, and I much prefer to hear the woody upright like tones i can get with the Jazz than with modern active basses. I also like some serious thump and growl on the leading edges of each note.
On the SVT I keep the mids a bit shy of flat or flat, and roll off a bit of treble. I rarely need to boost any bass, as I'd rather just turn way up and keep the mids clear and singing. There is enough warmth and fatness to the bass with flats, and from the SVT or VT that I don't have to EQ out too much treble, either.
What I like best about the old tones is that fine balance between fatness and clarity; nothing bugs me more at a reggae show than a bassist that is all about lows and no definition, growl, or punch, and no mids.
Our band play mostly various versions of classic riddims from the '70s, and we often combine a few versions into each song, which is fun for members of the audience who don't always realize the same bassline serves for so many familiar songs. We are bass, drums, one guitar, keys, and a tenor sax and a trumpet player. The problem is getting so many people together to rehearse and gig in what is essentially a hobby band, as we all are either working full-time or studying. There are no lack of potential gigs here, either, more the shame. Reggae has become so huge in Europe, really gone mainstream in many ways, and because of the Sound System nights and the amount of reggae that gets played in a few bars, the audience at our gigs is a very knowledgeable and appreciative one.
I tend to play the classic riddims very straight, and though I've written some lines I'm happy with, we don't do any original stuff live. As long as we can play nice and steady and try and do justice to those great golden age riddims we cover, and be ridiculously loud, I'm in heaven.
BTW, the drummer is a monster and without him there would be no band at all. There is no one else within 100k that can play reggae drums, never mind rock solid and swinging like him.