I don't see a problem with keeping the old varistor, since it doesn't affect anything.
As for the plug going into the transformer, I can't figure out the correct configuration for the jumper. I am not good at all with reading the schematics and I have no idea about the wire positions, since they are not numbered on the plug. I tried to make sense of it by trying to figure out my current configuration, with what I see in the manual, but no luck.
Can someone send me a picture, or a link to the information that I need? Thank you very much!