I'm not sure how you are using the webpage to estimate the absolute strength of any of the numbers. The table on that page is composed entirely of relative values. Each scale is essentially a zero to one hundred range.
Now if you look up the actual MOR of any given wood, I think that could be used. For example, green ash has a
Modulus of Rupture at 14,100 lbf/in2 (97.2 MPa)
View attachment 1132828
"You can calculate the modulus of rupture, "sigma," using the equation
σr = 3Fx/yz2 for the load force
F and size dimensions in three directions,
x,
y and z, of the material. In this case, the load is the external force put on the material of interest. The load force is applied to the center of a beam of the material elevated slightly above ground. From this experimental setup, known as the center point loading test, you can observe the deformation of the material in response to stress applied to it."
Now that is going to get exceedingly complex for calculating backwards from a known MOR value and applying it to the round (and tapered) handle of a cant hook. If fact, that looks to me like a downright daunting task to resolve.