Hey.
Looking good. From what I can tell from your pictures, it looks like you have been doing multiple thin, misty coats of the gloss paint. That's fine for covering with the colour, but for the finish coat, it needs to be a little heavier. There is a fine balance here when spraying gloss paints, as you need to put a fairly heavy coat on there, but not too heavy. You also have to do it all in one go, you can't just do a little portion, let that dry, then move on to another portion. To get an even glossy texture you have to keep going until the whole thing is covered. Gloss paint requires quite a bit of paint to be put on at once to allow itself to relax onto the surface (which must be sanded perfectly smooth) and form a nice even gloss finish. The danger of going too heavy in one coat is that it can start to build up and run and ruin the whole finish. If that happens, you will have to let it cure, sand it down, then try it again. I might suggest practicing on something else, a scrap of something, until you get the hang of it. Once you feel comfortable, take a stab at it on your helmet and see how it goes. After the whole helmet is painted and has fully cured, you could try giving it a coat or two of Nu Finish to really make it shine.
Hope this helps.
MJC.