Paint selection

How big is the truck?  I painted a full size truck (regular cab, long bed) with three coats using one gallon with a little left over for future touch up. But I did not paint inside the bed as I was spraying bedliner in there.

I typically get the same amount of clear as paint, but I like to usually do minimum of four coats of clear.  I've always been nervous about cutting through the clear. I've done it a few times and you have to stop and re-shoot more clear back on, essentially taking several steps backwards. I'm a lazy painter and only want to do the sanding/cutting/buffing/polishing once. It's easier to take more clear for shine, but once you break through to the paint...It's like getting your hair cut, it's easier to keep going shorter while sitting in the barber's chair. But once they cut it too short, they can't glue it back on.