Cab...I think I paid about 20 bucks for the 2.2 tip. I could not find the tip on the webpage, but calling them they had it. Also just the first set of numbers is the part number.
Frisco..I shot 2K primer with a 1.7 tip at school then used a 2.2 tip. The 1.7 lays down a thin coat while the 2.2 laid down a nice thick coat. with no runs. Mind you I am new at this. After I used both sized tips at school I bought th 2.2 due to how well it covered.