I would definitely try using the nails with the testors. Model paints are a lot thinner than most paints so that might help. You can also try to thicken them up a little by letting them sit out until the right consistency. Also, try laying the jigs on a table to put the eyes on and do one side at a time. I can not do it holding them in the air because my hands simply are not steady enough. Every time I try I get oblong and deformed eyes.
I love taking my kids fishing, now if I could just manage to fish at the same time.