Having spoke with a couple of proshop owners, when the arrow is shortened, it has the same effect as stiffening the spline. I've read that when shooting heavier broadheads, with short shafts, it may be better to soften the spline. If a carbon arrow is rated from 45-60 or 55-70, at 29 inchs, then you cut it down to 26.5 or 27, how would it fly with broadhead, if you are "stiffening" it? Thats why I asked about aluminum shafts. There are tons of combinations of thickness and diameter that might let you tune in broadheads better. I know the advantages of carbon, but with a fairly low draw weight and length, might aluminum be more consistent? Just a thought.