OK Carl some information to feed on. This is my recommendation.
Dump the AB brush in the drawer.
The Iwata is as fine brush. well engineered. I use a similar with a 0.35 for general work. Also has a top cup where you can add colours & thinners etc straight into it.
Paint. Well this is a hot bed. Every one has there ideas. Most descend on to one brand. I have. Reason is that I have become used to it know what I can do with it drying times how forgiving it is.
You have heard about Lacquer paint. So the best is to get a pot & try it. Do not go mad & buy a lot. Try it first to see if it suites you.
I use
Tamiya XF & X range. This is a sophisticated range of acrylic Paint. It is thin & you will not loose any detail panel lines etc in fine detail. Try that just one pot.
With a lacquer &
Tamiya you will have the best of paints.
I would get a large empty plastic drinks bottle. Spend lots of time with this selection of paints trying them out. Close then 150mm away different setting of PSI.
Spend a couple of hours it is worth while as you will learn a lot about the paints & the Iwata Brush.
On your disaster there are half a dozen reasons that could have happened. No mention of primer. I as said use the
Tamiya range. The primer I use for that is Stynlerez which is superb.Not a Lacquer man so cannot adivse.