A common problem in many games that use stand-up targets is after awhile the targets lean backwards and will throw the ball up into the air, causing it to fly all over the place, get stuck or break other areas of the playfield. Here’s a quick little trick to reduce this from happening.
My Mr&Mrs Pacman was notorious for airballs off the same standup targets as you are trying to remedy.I don’t (with all due respect) agree with using adhesive expanded styrene as a cure. For in-home usage you can simply bend the steel piece forward once every couple years,no big deal. If you must use the styrene you should apply it to the back of the target itself making it fairly invisible if you cut it to an appropriate size.
You should also have mentioned to do a final check to see that you’ve allowed enough room for the contact points to easily close. This is my first look at your Facebook page,I’ll bet I’m going to enjoy it! I’ve got 18 pinball machines,I see you have a Cleopatra as well.
Good suggestions. Yes, it is important to make sure the backing does not interfere with the switches. I may play around with other options but for now, the way they are seems to work well.