I developed it from experimentation and extrapolation.
Another poster gave me his load of 25 gr Pb with 1 1/8 oz/
I use 23.5 gr with 1 1/4 oz . Pb uses about 79-80% of the 7625 loads I have found and 23.5 to 25 gr is right in the percentages of 7625 suggested loads for the 10 ga.