Orange peel is caused mainly by paint going on to thick (too wet )and not flowing out (leveling) you want a light tack coat , followed by a couple of wet coats, spray just long enough to see that it's wet looking and basically push or move the wet paint across item being painted,you do not need a particularly wet application of base coat because it does not need to shine , not flowing out is mostly caused by the wrong reducer hardener for the Temperature , reducers come in basically four speeds, spot is fast setting for small jobs that need to be pushed out, sets in around 20 min, low med & high temp , to match your air temp a good quality clear will take what seem forever to dry , the slower it dries the better it flows out, here's, how you wan it to turn out, the whit specs are just loose dust from outside, notice the lower right corner of the tank , you can see a tad of unlevelness where it has not been rubbed out , that's a little better than new car paint, that's what you want, if your matching panels on a car not to show smooth, as far as guns go hvlp or lvlp or lvhp(old stile), has nothing to do with whether a gun is siphon or gravity feed, they make them in both stiles, as far as paint goes find one you like and stick with it, if your painting pearls light dry looking base coat is what you want to lay to keep the pearl or metallic from moving and mlotting together in spots, the link to the auto body forum is your friend, the youtube video's are your friends, the product data sheets are your friend, have fun, if you mess up thats what sand paper is for