Any Good tire shop will be able to do the mounting with no problems. They use machines that has the mounting arm locked in place so that it doesn't touch the rim. However, I have found several local garages that still use the old machines that ride on the rim. I prefer powder coat, but if you use paint, it Must be Fully Cured. Even though the arm doesn't touch the rim, the tire bead has to slip over it. Wheels that you painted last weekend won't be hard enough to keep the paint from rubbing off the sharp outer edge.
Good tire shops can do things carefully. One shop I use have mounted 20" 3 piece rims with everything powder coated and barely left a smudge.
