I had to replace some inserts on my ST:TNG after a mishap. I purchased a replacement set of inserts stickers from Ebay. After installing the new stickers I waxed the playfield and the ink came off If you get the replacement insert sticker kit just make sure it has lamination applied over the ink.

I ended up making my own out of transparency film. I printed the artwork as a mirror image so the artwork is on the bottom of the insert. They turned out great, you can't tell they they have been replaced.

They only down side was finding a glue that didn't damage the artwork/ink, plus the artwork took me a long time to make and size correctly.

For any other target decals I would use a vinyl rather than paper. I just don't think the paper will hold up very long.