Overspray are you calling waiting 60 minutes a wet coat?? Also there is not any solvent used for spi epoxy, it is epoxy and activator 1 to 1 mix and that is it.. You can reduce it if you wish to make it a "sealer"
FYI I have applied filler over epoxy in this fashion without issue, I have also done work and then covered with epoxy without issue, I have sprayed 2 wet coats waited overnight and then worked with the epoxy... again no issue's...
Although I have never worked for a paint company, I have had the pleasure of knowing a chemist in this field too
He agree's with the methods I have spoken of