DMD - you may need to look into the "rear window defroster paint" method. I did this on my Lethal Weapon, and it worked pretty well. Search here on Pinside if you're not familiar with it.
Trough - I don't have my Lethal Weapon handy, but is there a simply adjustment to the metal where the ball comes out of the trough that can keep it from going so far up the shooter lane? I had a kind of similar issue on my Getaway recently, and I just bent that piece of metal and all was good.
Jeff