I agree that the 5.0 ratio in my analysis results in an impractically long airgun.
But there are plenty of ratios say from ~1.0 to 2.0 that still result in a practical length.
I disagree that we should prioritise fixing B+A length over stroke length and bore diameter.
When I designed my pump I had certain tube stock that could not readily change diameter,
and I wanted a certain swept volume output, so stroke length was fixed.
However it was quite practical to give or take an inch or two from the airgun's length,
so the B+A value was given flexibility.
One thing remains constant: there's no fair comparison when you have so many variables.
To make it a fair comparison of one imposed parameter, it's unfair on the others, and vice versa.