Try to find a galvo firm close to you, so much easier just to hand them over and stops them looking rough a year down the line, people will pay that bit extra if you explain to them the benefits.
Hi build vynil onto galv. Only estate post and rail gets no galv. The client either has galv or they get someone else. I don't want my work looking shabby after a few months or couple years
Hammerite is formulated to work best on rusty steel, on clean steel it is too brittle and chips or just flakes off. I agree I don't like powdercoat because any compromise in the surface because of damage and the corrosion spread underneath will little sign until it's quite advanced. Any good enamel over primer and/or mordant solution over Galv, with the sharp edges rounded because no paint likes sharp edges.