Spray paint is too messy and smelly for me in the workshop.
I use cotton wool buds or paint brushes.
But I don't always back paint, I mix a drop of paint in to the epoxy mix, that does work but has to be well covered and tubes rotated many times to help get the air out. I have been know to have failures with it, just like painting as well..
Find the best way and stick to it. Init..