I use 1.8 cause I feel my body work is good enough where I can use a small tip and it saves primer but a 2.0 is better, I admit. When it's in the 80's+ I use a full cap full of lacquer thinner for every 12-15 ounces and this greatly reduces dry spray. Better to start on the side with less and evaluate how it sprays immediately. If it's too dry at the edge of your fan add more thinner and mix it in your cup. Any gun is fine at the recommended psi. Mix less in hotter weather. Not a great idea to add less hardener and mix a bunch. If you're doing a complete and mixing individual 24 oz cups or above, AND it's hott, completely clean your gun out after two mixing/ spray sessions or you will start shooting out little hardened pieces of primer. WHen it's not hot you can spray your whole car mixing a couple times without cleaning your gun til the end, but not in hot weather. It's very spray friendly. Doesn't run and is not finicky as a 2k.