Warren, the technique I described above I have done with an Iwata w77, a Devilbiss jga, a Graco airpro and I don't remember what other guns. Most have been 2.0s but sometimes I will use a 1.8. The last time I did this I used Ilva products. I have also used PPG, Dulux, International and other products I have forgotten. I suppose I have to remember I have been spraying for a while but the last time I got out a buff was because of a bug landing and going walkabout. I had to buff the whole cabinet then because the gloss dropped a bit. I personally believe a buff is to fix up later what I should have done correctly in the first place.
I get a little edge roll on the lower edge of a panel but never the face. The 2mm radius is important for controlling this. I don't know what else to say. The technique just works. Cheers
Every construction obeys the laws of physics. Whether we like or understand the result is of no interest to the universe.