If it really mattered, nobody could use 2-blade headswhen using 3-fletch arrows and get decent arrow flight. Just as a point of reference, people have been doing quite well with that kind of rig ever since the Stone Age.

Squirrely arrow flight means bad bow tune, shooting form errors, broadheads not in alignment with the arrow shaft or insufficient fletching size/offset/helicalto properly control the broadhead. Always. Blade orientation to the fletching doesn't have anything to do with it.

The only time it really matters is if the shooter truly believes it matters. Archery is 99% mental and if you are bothered by something, you're not going to be concentratinglike you should.Lack of concentrationcould let your form slip and cause bad arrow flight.So, if it gives you confidence, then by all means orient your blades to the fletching.