Let me put it this way. I can shoot a 2216 out of my 66#@29" longbow with 125gr tips. Thats the same asa 84-86# spined cedar. Your at least drawing 72# if your hitting 31" string to "back" (not belly). If its stacking (which is artificial wieght after stack), then you are close to 6 more pounds than my bows. I suggest a 90# cedar. Lots of people make em.
I recently got Paul Jolon,
http://www.elitearrows.com/to make some arrows, and they were quality shafts. He will make you what you want.