i spray 1-2 gallons of 2021 a week.
it is a good clear. it has excellent color hold out and durability.
i agree with what other people have said. use the highest solids clear you can afford. you will be happy you did in the long run.
with that said i painted my own car with Shop Line products from the primer to the clear. it has held up well.
the shop line clear is best in a air dry situation. it doesn't like to be baked to dry even with using the baking catalyst.
i can't comment on 2021's performance in a air dry situation because i haven't painted a car that way in over 20 years, it was always in a down draft baking booth.
one suggestion for best performance is to use DX84 ENHANCER, it's 84 or 87 i always get that # mixed up just ask for enhancer at the paint store, in the clear. this product will cut cure time in 1/2 but won't change the pot life.
after clearing wait a week before you sand and buff.