I was looking into this as well as I make the switch from mechanical to fixed blade heads this year. I am leaning towards using the 125 grain Magnus Black Hornet Ser Razors. My other questions are in the same 3 vs 4 blade conversation. Does a 4 fletch help throw a 4 blade fixed head better than 3 fletchings? Does it all come down to surface area of your fletchings and 3 would be fine? I need to do a lot more research to find the perfect setup.