I was a very early adopter; within weeks of buying my K12S and modified them and moved them to my K13. I'm 5’10†in my boots but have 33†inside legs so with a short back
I found/find the K12/13 to be a long stretch on long hauls. I wouldn't say the Helibars are the total solution. For that you need a K12R top yoke but that gives you a much more upright seating position and if I were going to go that way I would buy a GT.
For me, the Helibars knock the edge off the stretch but the biggest gain is sitting well for'ard on the tank a-la off-road posture.
If you are within spitting distance you can try mine.