Personally, I don't sweat the painting that much. You're more likely to scratch the paint getting it into your car. Actual launching will also cause dings and scratches. When the NC swings around and hits your fins, that's called the Estes kiss because the rubber shock cords in the kits are crap. When I paint, I paint to the full 80%. It's also a question of how good do you want it to look, 10' away, 5' away, or up close? I usually go for 2' away. Don't forget to take a picture of the rocket before it lands in a tree or a lake.
The beauty of the portable paint booth is that the spray gets captured on the filter as the air is drawn through with the floor fan. If you put another fan at the window, then the smells should also travel out. The odors last about an hour, but the paint doesn't fully cure for a day or two so don't lean it against anything or it will dent the paint.
White primer is chalky and easy to sand but it will run so light coats. Grey primer is gummy and hides many mistakes but will also gum up your sandpaper. I use 0000 steel wool on the primer then use a little baby powder to keep the sandpaper from getting clogged with primer. Some people wait an hour between coats, some wait a year. Your choice. Personally I wait a day. Paint crackling and splattering are problems that can occur.
Hmm, John Lennon and Yoko used to live across the street from Central Park...