I used the original right wing Grizzlies spinning them correctly with RW feathers for a couple of years and then went to spinning incorrectly because I prefer to shoot left wing out of my longbows, that finger cut from the quill thing, I hold so the arrow rides on my finger. Then 20 years or so ago I went single bevel Hills, I did that so I could grind them to match the left or right wing feathers. I was not considering cutting, I was thinking more of the aerodynamics of the broadhead trying to turn the opposite of the feathers. I wish i could tell that any of it made any noticeable difference in blood trails or even in flight characteristics, I cannot. I can say that a left wing or right wing single bevel Hill leaves more blood on the ground quicker than a standard Hill on average no matter which way it is spinning. Of course, I am not trying to shoot through a cape buffalo's shoulder bone, they have all flown straight through whitetail deer so far.