If he shoot 800 3 pointer made everyday during this summer. For 3 pointer, talent decides if you can become a shooter like Miller. But an average player can elevate his skill on shooting 3 pointers to next level by hard working.
I'd be happy to have Head as a third-string SG, behind Bonzi and McGrady, but that would give him very limited minutes. The best thing for him may be getting traded to a team that could give him some playing time, which I don't see happening with the Rockets this season.