To be honest, Bison is just like Strider Hiryu when it comes to assists.
Doctor Doom is the BEST way to go, ESPECIALLY when you begin to use the Warp to your advantage.
A prime team that I’ve seen work wonders is Bison/ Doctor Doom/ Captain Commando. Molecular Shield would practically nail your opponent when you turn them around with a Warp, and can be an easy set up for a Disperse Orb (HCB + P). And, of course, CapCom would provide some much needed air defense. Here’s a combo you can try:
(Have Bison as starting character) Call Doom, Molecular Shield, HCB + QP, D + FP, J. LP, J, LK, J. MP, J. MK, Weak Scissor Kick XX Psycho Crusher.
Note that when you perform the Weak Scissor Kick (HCF + QK), to cancel on the SECOND hit of the move. You can also cancel this into Photon Array or Captain Sword, but only to finish a player off.
Also, try timing the Disperse Orb so that it hits at the same time as Doom’s molecular shield, so you can get a few more hits in before you launch them with D + FP.
Hope that helps.