The theme of the fluid peak is something that you will not notice much difference, the 1.2 peak is to paint "thin" things, and with an air expense not very high.
On the other hand, the 1.4 peak is a widely used peak (in fact I have a ga-he with 1.4) and if you know how to handle you use everything, the only thing you owe more air (instead of 2.5 bar for 1.2 you put 3.2 for 1.4) and spray equally, only that it throws more paint and that the past are somewhat faster.
If you have extraction or paint on the street there is no problem, but if you put 3.2 or 3.5 bars painting in a closed place, with large pieces, (fins, skirts ...) it will form more fog.
In your case, what counts most are:
1º The
you
plan Mosquito Model Compressor, (1.5 HP, 25 liters 8 bar) You are going without air with either, (but it will fuck you more with that of 1.4 in large pieces). For example, I have a 2HP 100 liters 10 bars and I am left over for what I do. I hope I have resolved any questions instead of creating more.
All the best.