I have both guns and I prefer the 4000 for clear. The extra caps you probably won’t use unless you start using it for basecoat or primers,but if you just use it for clear chances are you will find a set up and stick with it. The fan pattern on the 4000 is a little softer. That would be my choice.
I’m with Ben on this one… Color is color ! If it matches great, be sure to do a spray out. However, a 2 coat conversion most likely has a lot of pearls in it and will not cover very well.
I don’t want to be a downer but you should watch out for film build with all those coats…. It will chip very easily with more than recommended film builds.
Everyone is right on with the heat. If you are in a humid summer climate with a cross flow booth it could be slow drying. Get your rep to let you try it first,and make sure you like it before you commit.