I just did mine last week. I masked all the letters with a strip of duct tape (or masking tape) and also all the bolts. Spray on the paint. Once dry, take off the tape and then use one of those little skinny kid's paint brushes or a q-tip and paint between the letters. Have a can of carb cleaner or something similar next to you. That way, if you get any on the letters, you can just soak a paper towel with some of the carb cleaner and the paint will wipe right off the letters. That's what worked well for me!
Tim 1990 300ZX Stage I Twin Turbo 1991 300ZX Stage III Twin Turbo (just added to Z family)