RE: Carbon Express Maxima 250's or 350's
Hold on before you fork out the $$ for a way overspined shaft...
My DXT is between 68 and 70 lbs with a 27" draw. I've experimented with shafts from 26" to 28" long. According to OnTarget the optimum spine for that setup ranges from .400 to .430 roughly so the 250 (or anynear .400 spine series shaft) is what you want, but make sure you go with a long enough shaft to keep above the 5 gpp min. Some of the CX shafts are pretty light.
I ran some numbers and you'd have to have a 30" shaft if you went with the 350 series, if you put more weight out front then that would change things.
PM if you need more info