Jon,
Are you shooting a recurve or longbow? Fastflight string or Dacron?
A longbow would likely require a slightly weaker arrow. Fastflight would increase teh spine weight needed.
I would guess 65-70 pounds for longbow or 70-75 range for a recurve, but I am no expert on wood arrows.. What I would recommend is buying a test kit for whatever wood arrows you plan to shoot. I bought a wood shaft test kit, douglas fir shafts from Surewood shafts. I believe some of our sponsors sell wood test kits for Port Orford cedar as well. You can also purchase field point test kits to see what weight tip works with differenly spined arrows.
The test kit may seem like a hassle, but you will be able to find the right arrow for multiple bows. If you have any friends that shoot trad and may want to consider wood arrows, see if they will split the cost for a test kit.