Self bows are real individuals when it comes to spine, but assuming a centered string, shelf well out from center and a 31" BOP arrow, I would figure 50-60 lb spine. Ramin would be a great arrow wood if you can find the spine. Doug Fir would be my choice. Spine and desired weight should be easy enuf to get. I figure a shaft around 400-450 grains.
I have some test arrows: 50, 53, 53 and 59 lb spine full length if you would like to try them. They have 125 points on them and I don't think I have any 100's, but that should be easy enuf to adjust for.