Use Intercoat and activate it, I've used it for pearls and the larger Ice pearls and candies with good results-just like spraying basecoat, use slow reducer and walk the whole length of the car double coating with lighter coats and 50% overlap. Your ratio of pearl to clear could also be too strong causing stripes. The object is to put it on slowly so you have more control. I've stacked 7 coats of activated intercoat reduced 150% over 3 coats of activated base and topcoated with UV clear with absolutely no chipping problems-the intercoat is a very durable product for a bc. Activating it is key for durability when you're putting a lot of layers on. Works great for candies also. Give it some time to release solvents before applying the topcoat clear-overnight is great.
I don't use my LPH for metalics-it just blew the paint apart too much when I tried it-But... Jeremy has good LPH luck with lower pressure so that might just be the key for metalic basecoats. My trusty Sata Jet90 works fine for metalics.