My son asked me recently "how do you mount new tires without scratching up the new paint on the wheel?. This is the technique I showed him that I've used for years.
First prep the wheel, clean, sand and paint the inside of the rim (if necessary) and allow to dry.
Mount the new tires and leave the beads unseated.
Take an old inner tube the size of the wheel (never throw away an old inner tube) and cut it in half along the inside and outside circumference. An 8" tube in this case.
Stretch the tube half between the inside of the rim and tire bead and apply your paint.
Remove the tube half once the paint sets and inflate the tire.
No chips, scratches or touch-up required!