I don't really use a primer. I just make sure I've sanded all of the old paint off of the plates and use numerous thin coats to make sure there's no clumps and the paint covers everything. For my paint, I usually use Krylon Metallic spray paint for both Silver and Gold. Just watch out, though, because silver can take a little long to dry. As for a finish, I use Pledge Future Floor Finish. This comes out extra glossy, but works like no other finish. I would highly suggest using it, but if you want a matte finish, simply use a clear matte spray finish OVER the Future. I hope I answered all of your questions. And just remember, when you're spraying, take your time and spray in thin layers
Hrm. Honestly, I've never met a scree that was too tight to unscrew. I'm not sure what I could really suggest. Some people say that if you use a hair dryer/heat gun to soften the plastic a bit, you should be able to get it out easier, but I'm a little wary of trying that technique myself. I would consult someone from the Radicons section on TFW. They should be very helpful over there