As for the spine question, I don't have a clue. But as for the dye, you could use leather dye. As for the saw sawing? I would think you could heat it to bright cherry red, and then let it cool down, and then use a metal blade on a band saw, and cut, and shape your knife, or arrow head, and after getting it shaped, you can heat it again, and dump it into a vat of oil, or if you want it super hard, dump it into a vat of dry ice, and acetone. For a knife, I would dip just the cutting edge, and then after the knife has lost some of it's redness, and is a very dull red, I would then dip the rest of the blade in. That way, your edge will be super hard, and the rest of the blade will have less hardness, and will take more abuse. You might wait for someone on here that makes knives, and has more knowledge, and experience, to give you a better idea. I have made some, but not like Mechslager, and some of the others.
Wayne