Re your buddy’s BM66 - I’ve never seen one with any major hangups.
When I first got mine, the turntable needed levelling - a slow lock shot would sit on the lip of the turntable.
Lift the playfield - at the bottom of the big turntable there are 3x brackets with a 10mm bolt on them.
Have one guy stand to the left of Machine, loosen the bolts off a little and have him hold the turntable so it is level with the PF. Then tighten the bolts up tight. Fixed!
Haven’t seen a problem with the bat mobile spinner - maybe check the game is level and at 7 degrees (mine is 7.5) and see how it goes.