I broke down and bought an arrow shaft cutter the other week and I honestly do not know what I did without one.
Since I started tuning spines with shaft length primarily and point weight secondarily, I've been able to tune three different shaft types in no time.
The whole thing is almost so easy it's embarrassing to think I had trouble before. Pick a point weight that causes a weak reaction and cut backward 1/4" at a time until the bare shafts are hitting well.
Yes I know, common sense, but without a cutter close at hand the game was sooooo much harder.
If you're on the fence about buying one, I recommend you do yourself a favor and get one.