point 15 in the draft is not on the vertical line squared down from 12.
It states that point 15 is 1/2" from point 12 but places 15 closer to the CB- kind of in mid air- so maybe it is 1/2"down from 12 and also 1/2" in which would reduce the back neck size.
I agree that its really complicated and it doesn't have to be.
Placing point 15, "1/2" from 12", caused me pause. I decided that rather than on a square I should take the measure on the sweep, and that course put it right about where the diagram shows it should be. And the measure it provides seems to work out -- I'm assuming my "correction" is in fact what I call it, until somebody can show me how to make better use of the draft.
And really, considering what I've been struggling with, this is average -- you want complicated? Try the Keystone system (NYC 1895). The system takes five octavo-size pages, and four diagrams, to spell out the basics. Then a similar number of pages and diagrams reviewing its nuances and mentioning variations. And this only covers the front and back, eh -- we still have the sleeve etc. to discuss ... Absurdly elaborate, yes? One of the reasons I'm here is to better understand how this stuff compares to what's standard today.