I got so far but don't think the balls rolled in the right way for me to cross this part: Spoiler: screenshot
@shaun Roberts your welcome have you played this level? https://mekoramaforum.com/media/last-star-ball.29522/ just B only.
Thanks to @Ray Aznable, I was forewarned about ball direction and, of course, I pushed one the wrong way. But, I recognized the error right away. Experiments showed the correct order. Then it was just the issue of the zapper corner, which got B a couple times. Timing is tricky for me. Got the win, tho.