#1
I really tried to search for this so that I didnt start a thread that didnt need to be started but I didnt really know what to search for so nothing useful came up.

Im building a guitar right now and I really love when custom guitars and basses have wood covers over their pickups. Some are actually integrated into the pickup but I know some are just caps, more or less. My guitar has a lace wood cap and I want to make a matching lace wood cap for the pickup but Im not sure how it needs to be done. For instance, some have exposed pole pieces, some dont. (my pickup is an emg so the pole pieces part really doesnt apply but I would like to know for future guitars) do you need to have exposed pole pieces? Do you need to have the cap a particular thickness in order for it to not disrupt the sound? Does it even effect the sound at all?

Anything you all know about the topic would be helpful!

here is a link of what Im talking about
http://www.alembic.com/info/doubleneck_details.html
#2
I think your best bet would be to have a veneer cap. Most those guys put the cap right over the pickup windings, but I doubt you'd want to tear apart your EMGs just to do that. Go pick up some lacewood veneers and glue them on. It'll take some time to get a really clean cover, but I think you'll achieve what you are looking for.