If I recall your earlier post, you where shooting 51#, SK, and drawing it 30 or 31 inches, but you did not mention the point weight. If it were me, because wood shafts are spine on 26" centers, add for:
3 inch, 5#/inch over 28", = 15 lbs
FF string, 5 lbs
Center shot 5 lbs
Point Wt., 5#/25gr over 125 5 lbs
Total 30 lbs
That might suggest 75 - 85 lb spine especially if you are shooting 160 gr field points. Add more if you go with a heavier point or broadhead. Next put some medium wt. kraft paper on a box frame (wood or cardboard) to paper test. Elite Arrows tells you how on their website.