Someone emailed this question and I thought I'd share this answer here:
How big are the paintings or rather I should ask how thick did you apply paint?
I use Winsor Newton paint and usually spray a retouch varnish (Kamar) when paint is dry to the touch which is usually three or four days. The reds usually take longer, but no more than 2 or 3 days.
Conservators would probably tell you to wait 6 months. I guess you can respray after that amount of time.... Maybe I should respray all the ones I still have here? I'm sure a conservator would be better equipped to answer but that's what I do. I can't wait to see the colors come back to their origins.