Re:
Well done , a nice sympathetic restoration
The brake straddle cable lengths are often different ie longer on the front than the back
The mechanical advantage is much greater as the straddle gets shorter , so a brake with a short straddle is
more likely to lock up than a longer one , and would have less 'feel' which is not ideal on a front brake
Check out Sheldon Brown on adjusting cantilever brakes for info on mechanical advantage
I suspect that the original straddle cables were correct , as your new front cable looks on the short side to me
One small detail , the straddle cable hangers are usually fitted the other way round with the cables ' out of
sight ' from the front and back views