i have the hp-c and you can go get new tips for it. .4, however it still spits w/ metalics. i think it has to do w/ the shaft that the paint has to go through. as it goes down the shaft and around the needle the space becomes less, and makes it harder for flake.
the eclipse has a larger volume area around the tip w/o that shaft to go through. the eclipse also has different tips you can get. a .35 and a .5. if you have the eclipse that's the mod i'd make for flake. your out of luck w/ the hp-c i beleive.
i do like the .4 tip and the .3 needle combo i upgraded my hp-c w/. it shoots a little more media when you want it and still has very fine detail.