For right now stick to what works. If you're bigs and forwards can draw fouls in Princeon than that and LI could be good go to Offensive tactics.
Defensively I've only run M2M and 3-2 so I can't really give advice beyond that.
Sucks that your bigs are both down right now... but at least they are only "1 week" injuries. So hopefully they be back by next Tuesday at the latest.