I may be talking rubbish here, but I did a little research on this when I received my Richards chassis in the summer.
Isn't that a rust-stabilising paint? Would you really need that on a new galvanised chassis? I would have thought Corroless M (Multi-Metal Primer) would be more appropriate.
I used Rust-Oleum 3202 Galvinoleum Primer when I did mine - weird stuff, like painting with really thin glue. Seems to have worked reasonably well, but since it's still a long way from being on the road, I really don't know how well it's going to stand up to (ab)use! I'll look at using Corroless when it needs patching!
Are you planning on washing it with Ammonia?
The other thing I heard is that the more weathered the galvanised surface, the better. Their chassis really are very shiny when new, so if you have time to let it sit outside a while before you need to paint it, that might also help. You've picked a better time of year for it than I did!
Good luck with your rebuild!