I have tried your recommendations however I think I have to modify it. Please see the attached picture:
Here is my sleeve pattern.
I think when you have recommended to add ease to the bicep line, it is meant to add ease to the B2-B5 lenght. As it is calculated from the shirt pattern armscye for this method I use, I have to add some ease for that calculation. When I do that, the point B5 slides toward the point B3. Is that you recommend?
If I do the above manipulations, the sleevecap (B-B2) does not shortens. (Just proportionally shorter compared to B2-B5) For my sleeve pattern drafting method, that lenght (B-B2) comes from the shirt pattern armscye height. I can shorten that if I use a different factor.
The "arm_upper_circ" measurement can be seen as B15-B21 lenght onmy sleeve pattern. I do not use that measurement for calculating the height and width of sleevecap.
I am still thinking and fiddling with my pattern using all the recommendations and experience I collected yet.
I am working currently on patterns for skin tight garments like lycra, etc...