I seem to be getting lucky, because whenever i have 2 matches in the same day, they're separated by enought time to the team recover 15%, and/or one is a tought match and the other is an easy one. So, team rotation, substitutions ingame, and a couple of rest packs (by friend and matches) have been enough to allow me to play with good condition (> 90%, at least, most times above 95%).
Tomorrow i have a match at 9am(local time), and the following at 17h. So, plenty of time to recover recover a bit. Using the 3 substitutions i can spare some of the players, giving them time to fully recover, and perhaps spend a couple of boosters on 2 or 3 that get in worst condition. Unfortunatly i can't do much of a player rotation, as both games are very important (last game of CL's stage group and the morning match is against one of the top teams in the league).