Based on recommendations from other builders, I decided to prime using Stewart Systems (www.stewartsystems.aero) 2-part EcoPoxy water based epoxy primer in smoke grey. Before spraying the actual parts I experimented with preparation workflows. I decided to use the following sequence:
1. wipe down parts with solvent to de-grease.
2. spray 2:1 water to EkoEtch and scrub with maroon scotch-brite pad to aid in the etch
3. Rinse and dry
I sprayed the 2-part per the instructions and tried for a minimal but continuous surface coating. I probably tended on the thicker side. As I get better I hope to get the best viscosity, pressure and flow set up on the spray gun.