Hello, I want to spray paint a roller garage door with RAL anthracite grey ( 7016 I think? ) but not sure which paint to use? I will be using a portable paint system ( not Graco btw! ) but not sure which paint type would be the best to use. As far as I can tell the door is aluminium but coated with possibly a type of chlorinated rubber? It has a smooth, softish feel to it so tipping it might have an amount of elasticity to it. Maybe for thermal reasons and durability? I have seen you recommend HMG, Cromadex and Zinsser for similar jobs but not specifically to cover this kind of finish. Can you point me in the right direction? Thanks in advance.