the helmet is lookin sweet man that is fiberglass matt and resin right? i thing that is the best way to go with these. i would finish it off with some glazing putty. it is sort of like bondo but a little softer and more flexable it is easier to sand ( good for strangely shaped surfaces ) if you have a fiber glassed helmet reinforced with foram you shouldn't need you finishing material to be super strong just enough to give you the glassy finish you want.