10.5 w/can, sweet! It seems heavy but, will be a stable setup you do well with I bet.
On the trigger, not advocating you modify new parts without thought but, might could clearance a scootch to roll with it, so long as your not changing the hooks it shouldn't affect function.
Won't clear the bolt? You said upper, I'm not quite with ya on what's going on there. It could be an out of spec catch.