One word of advice I would give, is that whenever you cut a carbon shaft to adjust the spine, do so in small increments. 1/4" goes a long way towards making a carbon shaft more stiff.
It`s hard to imagine an arrow flying right with 250 grains on the end, but believe me,they do.
I steered clear of carbons for a long time, but now I`m glad I put in the time to learn how to get them to fly.
In the long run, because of durability, I believe carbon arrows are cheaper than any other arrow.