OK, this topic is not really on Passive House.
Hot Dip Galvanizing in Toronto:
Cost: Rough Ballpark is $.40/lb of finished galvanised item, $295 min charge
Spec: ASTM A123, min thickness 3.4mil or 610g/Sqm or 2oz/SF
Tubular sections will require holes about 30% of section width each end of frame/item.
Bath is at 840deg F, so no sealed sections will be allowed due to danger of exploding, though part can also float in the molten zinc bath.
Partial dipping is possible but there can be practical issues with the conveying machinery and part set-up - so it depends on what the part looks like - shape, etc.
I love finding out stuff like this.