Just can say :
Do it , the higher the better .
This is the first time i did Ape on my bike and i love the feeling , the comfort , the handling - increase .( I did not believe before )
I also wanted the PY , but ended wit a V-team (here in germany we need the handlebar to be allowed and the PY is not- don`t ask why),
The pullback on mine is 7" (the height 18") and i can lean the bar forwards (negative angle to the fork-direction-very cool).
I would do it again , and i am glad that i waited so long to become encouraged for the 18" height , a year ago i thought also about a 10" or 12" height to keep the brake and clutch lines, but gladly i did the higher one , it is worth to change the lines .
Ape rules !