[simon miller]

If the string is twisted to get peep straight, then does it also afect the bows tuneing??

 

[TMan51]

Depends on how you do it.

If you put a turn on one end, and take a turn out of the other, not.

A half turn is not likely to make much difference as far as tuning goes, but you should check flight, especially on very fast bows, with more critical design features.