I agree with Rob - if you want light heads I'd recommend the Woodsmans (Woodsmen?) - the Snuffers were designed to be the full sized heads (160 gr without adaptor) and to make them smaller they just grind more off. The 145 gr heads (without the adaptor) are OK, but I REALLY don't like the 125 grain Snuffers - they took too much metal off. I thought guys talking about failures with Snuffers were full of BS....'till I saw some of the 125's...Now I understand that. You won't wreck the 160's, the 125's, I ain't so sure.
As far as penetration goes...theories are great, but for whitetails, bears, etc. if you are at 50 lbs or above with a reasonably performing bow, penetration comparison is a non-issue, as far as I'm concerned. When I was in high school I shot thru several deer and bears with full sized Snuffers out of 52-53 lb bows, no problem. That was before "broadhead lethality tests" and the Internet though, so maybe the animals are tougher now.....
Ryan