I shoot a 45#56" Darton Valiant and a 58#/60" Darton Classic SL. Both are older bows using Dacron strings. I fletched all arrows with 4" shield cut RW feathers with a moderate helical. These are the same 10 year old shafts I used on my old compound with plastic vanes. I simply replaced all nocks and feathers. I made half a dozen cedar shafts up spined 45#-50# and got terrible groupings between the two bows, with kickers to the right or left respectively. Not so with the 2117's. Charts recommend 2016's for my lighter bow.
I have learned to "hold" a little lower from 5 to 20 yards with the 58# bow, but always assumed it was because the heavier bow was faster. Out further it doesn't matter between the two. If I held the heavy bow the same up close as with the lighter bow the group would be about two inches higher, but still centered. There must be enough overlap with this spine in the old XX75's.
I have never paper tuned, but all arrows impact targets at the same angle, and watching them in flight shows no fishtailing or anything. I know it is odd, but it has just been my experience with my old equipment.