The small block is pretty similar in concept to a creamback, and they match well with Splawns once they wear in and take some of the peaks out of their treble response.
Definitely agree with @311splawndude that V30s with Splawns can be pretty intense in the mids, my Super Stock through a friend's Randall 4x12 with two V30s and two creambacks absolutely deleted a VHT Pitbull and a Mark III out of a live mix a couple of years back with the mic on a V30, we moved it to a creamback and it balanced out a bit better, but in live situations Splawns will eat a lot of other amps because of that mid range punch and the sheer amount of air that they will move bleeding from the stage in my experience, (my other friend's '05 Pro Mod is even more pronounced once you start to ramp the gain up).
The Creamback/V30 mix with my amp sounded amazing though, it's just that it can be a thing to watch when you're doing a live mix, especially if you don't have the mid switch like OP.