Another win! Since I got the machine, the shot to the left jokers had a major springboard effect. Numerous shots headed up there would hit the metal bar and "spring", and ultimately reject and fall down.
I noted, a while back, that this was due to the gap between the metal guide bar and the rubber. Slowly but surely, I've been working the metal bar back, and now it looks like this:
When compared to the old pic, it's hard to see the difference, but the metal is now more curved, and the gap to the rubber diminished.
The end result is that game play is much smoother and faster. Very few balls are rejected due to sprinboarding when shot up the left.