Most of the pain in setting up a FD is in its height and angle, which you don't need to touch. I say go ahead and fix the cable tension.

What I do with FDs, is instead of allowing the tail of the cable to poke out where it's designed to, I wrap the cable all the way around the pinch bolt so it comes back out between the chainstays, and I haul on it with some pliers before tightening the clamp bolt and cutting off the excess. That usually avoids too much dicking around trying to get the cable tight enough, and is tidier as a bonus.

If you need to dick around, I find the best approach is to screw in the inner limit screw half a turn or so before tightening the cable - that way when you back it off again, hopefully the cable will grow taut at just the right spot and share the job of the inner limit screw. You can also loosen the cable slightly if need be, by carefully loosening the pinch bolt with hand tension on the cable until it moves with the bolt.