I have had trouble trying to tune carbons out of my Northern Mist bows, GT 500's and 400's shooting full length down to 28" which doesn't leave me room for a broad head as it will hit the front of my riser. I have shot 125 grain tips up to 250 tips. I could get ok flight and no noise from full length 400's, my brace height runs right around 6 3/4" depending on the bow model. My bows vary from 48 pounds to 54 pounds, I purchased a test kit from Surewood Shafts and settled on 60-65 spine with a 9 1/2" back taper shooting 225 up front, I have recently switched to 160 grain tips and am still getting good flight, the wood shafts do seem quieter, but may just be the nature of the material. I think part of my issue was with how the riser is cut and trying to get the shafts around it as quiet as possible. I also shoot split finger with a glove with these bows. I tried shooting 3 under like with me recurves, but just seemed to have more tuning issues, which again I thing goes back to how my riser is cut. Good luck in your quest!!
Jason
Terry, I think you should write a book about all the kills those arrows have made in your spare time!!!! That's awesome!!