The compressive force on the bowsprit must equal the sum of the components forces from the bobstay and the headstay along the direction of the bowsprit. Given that those stays are at an angle about 60 degrees to the bowsprit, and given that each staty must transiently take 100% of the load, and given a safety factor of 2:1, I figure that those stays must have a strength 8 times more than the compression on the bowsprit.
Thanks Rich, I don't get to exercise my engineering neurons very often any more.