I have used SPI products on 10 different paint jobs. Both planes also have their universal clear; also arguably one of the best clears for amateurs without spray booths (it is specifically designed for use without evacuation and it can be buffed at ANY time - no window). Their epoxy primer is probably the best all around epoxy primer in the industry when viewing all variables.
You won't be disappointed. Only caution is to not spray the first coat too thick, else you will get what resembles fish eye. You can hose on the following coats if you want, just not the first. Also, parts MUST be kept at 65* for 24 hours after application.
I do not agree that all epoxy primers are the same, especially when viewing adhesion and corrosion resistance. Not highly critical for F/G parts. Call the SPI tech line and you'll get Barry, the owner. Ask him what is different. I think you will be surprised.
Larry