I don't know if these are just rules for Georgia, but here, a player can play up to the number of games allowed for Varsity. In other words, Varsity is allowed 26 games, 1 scrimmage plus the playoffs. A player can play any combination of games that totals that. Doesn't matter when you play those games or who you play them for. So, if you play 16 JV games, you are eligible to play another 10 varsity games plus the playoffs. Hope that makes sense.
I also know for football you can play up to 6 quarters per week, Sunday - Saturday. So by definition, you can play JV and Varsity, just 6 quarters per week combined.