Yes I'm using the flexbar. That and ice right after a match helps the most. I've tried the PK 7G and I did not like it at all. Granted I demoed it with some crappy syn gut in it, but it felt dead. Like swinging a padded hammer. Easy on the arm but the feedback was poor for me. I did not like it. If I'm forced to I'd switch to it, but its a last ditch effort.
I currently prefer the Yonex RDiS 100 98 inch frame. I demoed like 30+ sticks 4 years ago and that's the one that felt the best to me all around.
I'm a one handed backhand, both sides western. You are right about the grip. The issue I have is a perspire heavily. The grip twists when it gets wet if I get too lose. Its the backhand side really where the injury is occurring. I can feel it if I hang on too tight and frame a ball on the backhand side. Ive tried all the popular grips and the Bab Pro Tour seems to work the best for me. I've heard that a plain old leather grip can work too, although I have not tried that.