You can sort of tell from this photo, but I put two black post sleeves on my rock crusher.
Works great.image.jpg

I also recommend adding a few spotlights.
I have one pointing at Joe's Dinner billboard, one at Bowl-A-Rama and one behind/under Dino crane pointing at the business guys.
The spots definitely brightened up the game....as did the Dino crane LED mod.

Pics of my spotlights and an underside pic of how simple it is to attach the spotlights with some insulated alligator clips from Radio Shack.image-106.jpgimage-36.jpgimage-768.jpgimage.jpg

I also used a half inch spacer on the spotlight pointed towards Joe's Diner to get a better angle and not have light reflect off the playfield glass.

I have the post sleeves and the ball(s) have never gotten stuck once.

And good luck with the bowling alley pins. I had to re-cut the metal flapper on mine.
Luckily it's just ramp steel and i had a roll of if it. But I had to borrow a buddies riveter to attach the new flap.

Oh, and if anyone's bowling pins tend to pop out from a ricochet or errant ball, I discovered a great way to keep it from falling off.
Find a thin, small washer and cut a slice into it. Then you can wedge it under the "T" section on top of the pin so it won't slip through.

Yours probably won't be so bad.
I replaced my pins with new ones when I tore down the whole playfield after picking up the game.
I had to replace the metal flap on mine because it was broken. If yours isn't then changing the pins should take a few minutes. And I had to use the washer trick because on of my slots the bowling pin fits through was a bit worn and the pin "T" head wasn't as wide as it could be.
Mine was probably a worse case scenario.

I believe it does run the whole time during multi-ball.
And it can hold on to the ball for what seems like forever. However, it's supposed to stop to let the ball drop if it hasn't after approximately 10 seconds.

It's definitely your switch to the machine causing it to keep spinning if the ball doesn't find the exit. The machine doesn't know it's in there.
Easy fix.
And jealous that you don't have to pay for parts shipping whenever you need something in a pinch!