What comes first?

[trig]

epoxy primer over blasted body than filler or body filler than primer. This is a slow moving project and want to avoid any rust issues. my car is bare metal in the interior and undercarrage and I was planning on using an epoxy than topcoat (yet to be determined ie. paint or undercoating). Before going top side (will be using da to strip) do I prime frist or skim coat?

I have read about southern polyurthanes on this sight with multiple positive reviews. I am not a body man (will not be doing final sanding or spraying), what are recomendations with their product line vs dupont, ppg ect? It is critical that I stay with same company all the way, or can I save some money for the epoxy primer?

Thanks,