GB5 Engine bay

[xpbprox]

So I'm planning on painting my engine bay with PPG 2306 as a Single Stage Acrylic Urethane which i have been told is equivalent to GB5 is this true and if so do I have to mix it with anything other than reducer and hardener to make it look original, how much of each of these?
Also I was planning on just shooting one coat of some Epoxy primer as a sealer also, then just painting directly on top of that. The engine will be sand blasted and I was thinking about treating it with some type of rust neutralizer in some areas, is this necessary?

Any help would be nice, Thanks
-Al