Hi Phil,
is there a shorter cable available somewhere?
A short answer is Yes (JJ cables)
The longer answer is that the suppliers information on fitment is mostly incorrect
The next part of the problem is that most pattern brake shoes are lined with too thin a lining
this results in the arm on the hub winding up at the wrong angle for best effeciency
then owners move the cross over lever forward to take up slack in the cable resulting in a *** poor brake
I was working on a late model A10 last week and went to correct the cable length as the inner looked too long
Anyway the ends were crimped
so not easily moved
I had another cable, and tried that, Bingo
the length was perfect moving the cross over arm two splines to approaching 90 degrees
The result is a good usable brake
The bike has gone back to its owner so I do not have the cable length to hand now
I modified the cable on my own 61 SR some years ago to correct the lever angles resulting in a brake that will lock the wheel
I can measure the length tomorrow if you need ?
John