What is the ratio of span change vs thumb pitch? Is it 1/16 change in thumb pitch per 1/8 change in span?

There was a post about this some time ago and I tried to find it and failed in doing so. I am thinking it said if you increase thumb pitch 1/16, to increase span 1/8 and if you decrease thumb pitch 1/16, decrease span 1/8 or something like that. Is this correct?

Eliminating all other factors...yes that is correct
1/8" equals a 1/16" of release angle

Thanks Rick. I am starting to not rememebr some things like that in my old age, so had to check to be sure. My current finger F/R pitches are 0. I am considering adding 1/8 reverse to them, so if I do, I probably should add 1/16 to span?

Don't make too changes at once
I'd adjust the fingers see how it feels the go from there

Ok, I will do that .... again many thanks