It would make me think the same thing.
Just a thought but have you thought about upgrading to a splined shaft transmission?
Doing that would definitely solve your cable availability problems.
Just a thought.
Upgrading to a newer transmission is something I really should have done when the original hub bearing went and took the clutch hub with it.....
But at the time I didn't know any better and just fixed what I had
O well, some day maybe a six speed will fall in my lap......