+x+xAll in all, its a solid plan. The Duratec will bond just fine to the unwaxed resin.
I agree with doing 2 coats - but I would probably recommend not brushing the first application on. Youre sort of giving yourself a lot of unnecessary work. Duratec can build really thick when sprayed, it doesn't need to be brushed on to achieve a thick coating. If you have little pinholes etc coming through, then fill those with a brush or a pin or something similar. You can either spray your first application, let it fully cure and block it flat, then spray your second application. Or, if you don't need to do a massive amount of flatting, just spray your first application and let it cure for half an hour and then spray your second application directly onto it. Then once cured, block and compound.
Hanaldo, thank you so much for your reply and advice. Happy New Year, Allen
If you are going to seal the foam with the polyester resin then you maybe could also do that with a tissue or other light glass. This will give you a tougher better surface to work on with final filling and primers. This is the way for me as it can be real pain to do final work on foam material that is softer than the primer.