Without having a lot of experience with my el cheap SSB, that's sort of disappointing to hear. Was hoping with how great my shoulders have felt the past few workouts since moving it over to my routine, I felt it work my anterior chain like a son of a bitch, but felt I could manipulate the core a lot by elevating/lowering the handles. To be continued...
Once it's set don't use the handles as more than hand placement. Enables you to cheat and rock the bar.
Theres a few curved bars which can help with shoulders. I forget the exact one maybe Buffalo or Duffalo (different bars just sounds the same). Is that what you are looking for?
Back squat is king for a reason. Not saying you can't SSB exclusively but it's not the same and ultimately not as great of a movement. That said, do what you can. I was focused more on carryover etc. If all you cam ever do is SSB that's still a hell of an exercise.