Can't help with the spine question but I'll chime in on the fletch cutting your hand.
First, I assume you are shooting feathers not vanes? Vanes and shelf shooting don't go together too well.
Second, look at your fletch. Right where the front of the quill ends, take a sharp knife and cut a bevel on the leading edge to taper it smoothly down into the shaft. Do every feather of every arrow then put a single drop of Duco cement on the bevel big enough to coat it well. Let dry and it'll shrink down to practically nothing and will look about like clearcoat. Run your fingers down the shaft and over the fletch. There should be no sharp edge or "catch" on the front of the fletch.
In the off chance that you have already done all this and are still getting cut, only two other things come to mind. First is too low nock hight as already said. Second is fletch position and or hight. Fairly tall fletch with stiff feathers like natural turkey can cut you with just the feathers after a lot of shooting. Fletch positon can make a differencd too. The cock feather that would be the one hitting your hand should just miss the top of the outer edge of the shelf and the hen feather should pass almost exactly in the "V" of the shelf. If all this is right, try nocking cock feather in and see what happens.