Hi Bill, I am just a hobby builder of only a few canoes. So with that disclaimer here goes. You can use any paint you want. Brushed or sprayed. My preference without question is Kirby's paint. No primer. Rub the filler as smooth as possible when you apply it. Sand it. Paint it, Sand it. repeat til desired effect. I sand most of the first coat off. Alot of the second coat off. Third coat is not bad. Four coats should be quite good. One thing about these various decisions I have learned, is that the builder is the creator and can do it any way he wants. BUT. the tried and true traditional methods are best. I was privaleged to visit Horace Strong over the Labor Day Holiday at his shop. He had one Grand Laker that had an awesome finish on it. He also had a very fine, very old canoe that had a finish that was like sandpaper. The builder experimented with a filler as I recall. Now this was an old and very nice canoe that I'd have been proud of. Just a bit textured is all. Having said all that, here's another suggestion. Check out the builder's catalogues. Their web pages are full of great tips from filling to painting and more.
Regards, Dave.