I use a 7G which is similar and just finished a trial of SPPP in a full bed. Arm wasn't even phased. Your mileage may vary.
Related, I also have a Flexbar and have been working on loosening my grip throughout my swing. Played last night with a poly hybrid that was quite stiff and had zero pain. While the Kinetic stuff absolutely helps, I think technique goes a long way, too, which is allowing me to use full poly from time to time. Again, you may have a different experience, but something to consider in your search for pain-free playing.
PK 7G w/BHBR 17g X Weiss Cannon Silverstring 17g @ 54lbs