I personally wouldn't use anything smaller than 1.3,since I use only high solids clear which is fairly thick, but depending on what materials you spray,1.3 and 1.4 is very common and if you don't spend 8 hours a day in paint booth, they will do just fine, as far as choosing between high end guns,it's very hard as most of them do awsome job at atomizing the materials,some guns feel different in hands and are easier to control than others,so it's better to actually grab the gun and feel how well it conforms to your grip, also keep in mind about the size of the cup,alot of the HVLP guns will put out so much material in so little time that filling it up every 5 minutes gets old pretty quick
