I think we can do better than so-called "random features".
It seems to me like a fairly safe bet that a 5/54 twin would reproduce the 5/38 crew arrangements in general, if not in exact detail. Thus a trainer on the mount's right hand side, a pointer and checker on the left, and a mount captain at rear center where he would be out of the way. And I wouldn't expect the exterior accoutrements to be different by more than a pixel or so in any respect.
Possibly the mount would be mirrored, but I can't imagine why. Stick with what works and minimize crew re-training and additional elements in the supply chain.
Colosseum is welcome to drop in with sources and completely invalidate everything I've said