Before I learned of the additional advantage of keeping the fletching and bevel the same, I used LW fletch with all of my Grizz heads and experienced excellent performance. This year, I switched to RW fletch with my Grizz's and had equally excellent performance.
On deer sized critters shot with reasonable poundage and good arrow weight, I would expect results to be good assuming a well-placed shot regardless of the relationship of the fletching direction to the bevel. Of course, it's always those marginal shots that get us into trouble!
Claudia