Personally, I'm kind of partial to the big Snuffers for some reason
I look at broadheads as a specialized tool designed for a specialized application. For 95% of my hunting penetration is, frankly, a non-issue regardless of broadhead size (within reason). For game up to elk size I am fully confident using the biggest Snuffers out of bows in the low to mid 60 lb range and have always gotten an exit hole on game. For really big stuff, when penetration becomes a factor, a smaller, 2-blade head gives the needed penetration. I shot several hogs with the STOS head on the buffalo hunt, and when hit right they went down quickly. In the cases where trailing was necessary, I was less than impressed with the blood trails on the passthrough shots, when compared to hogs I've killed in the US with Snuffers. My opinion-use the biggest head you are confident of getting an exit hole with, therefore guaranteeing the best blood trail you can get. There was NO bloodtrail from my buffalo (went 150 yards) but that was no surprise as you dont generally shoot through them with traditional equipment.
Ryan