the shorter straddle cable will increase braking power... the longer cable typically goes on the rear brake to decrease skidding.
the front tire can accept more braking force because of weight transfer when braking hard, so the shorter cable gets placed on that brake.

I've used shorter or longer strads to get around problems too.. racks, fenders, reflector brackets, odd forks, low cable stop bridges on frames, etc.

this is assuming that both brake levers are the same pull ratio, and not adjustable.
there are more variables to consider with canti brakes too... their tune-ability and shear braking power make them popular with CX racers that haven't switched to disc, or got tired of fighting brake squeal from their disc brakes..

here's a decent little primer on the subject of canti setup...
https://bike.bikegremlin.com/1739/ca...ke-adjustment/