Since I haven't had any solid bites on mine that is for sale, I've continued to tweak it so that it plays as well as it possibly can.
Wotan saucer no longer rejects, at all. Moving the metal piece behind the saucer took care of that.
Did the best I could to eliminate the ball hop from the lane guide to the flipper. Can't be fixed without a replacement ball guide, unfortunately.
Lastly, I learned something about the inlane that I never noticed before: There are actually three different ways you can configure it, to make it easier or harder.
The slingshot rubber can either go around the outside of the post where the gate attaches, or around the inside. On the outside, it makes the inlane very narrow and bouncy. I also noticed that the one-way gates hit the slingshot rubbers when you have it configured this way, so you can't have the gates in there with the narrow outlanes. This is the "brutally hard" configuration.
Alternately, you can route that rubber so that it goes inside the post. In this configuration, you either can use the gates (easier) or not (harder).
Look closely at the pics in this thread and you will see all three different configurations. One of the pics Aurich posted on the first page actually has the left and right sides configured differently.