I think both Traxxion and GP do the job well. I'd pick the one that's the closest, and if possible do a ride in.
This ^^^
In 2006, I had Traxxion Dynamics rebuild the forks with their AK-20 set-up on my 2nd Honda CBR1100XX Blackbird at 3,500 miles, with a Penske on the rear. Excellent suspension.
In 2010, I did a ride-in to GP Suspension on my FJR at ~ 35,000 miles to have them rebuild the front suspension (revalve, re-spring and adjust spacer length for preload) and to rebuild and re-spring the Wilburs rear shock. Result was beyond expectations.
Before the GP rebuild, I had clearance issues with the FJR suspension compressing enough mid-corner to scrape the Muzzy 4-2-1 exhaust collector when it bottomed out the Wilburs rear spring. (At 5,000 miles, I had installed stiffer than OEM front & rear springs and Wilburs shock).
While replacing the front and rear springs, the GP tech explained that FJRs were notoriously undersprung (esp in the rear and even aftermarket) and dialed everything in, all the while explaining what he was doing and why (the ride-in was well worth the money). The result was almost unbelievable. It actually felt (1 and 2 up) like there were fewer jarring shocks (plusher?) while being firmer and more planted when pushed hard in sweepers and hard side to slide twisties. That was 2010, and I have never since scraped the Muzzy collector.
Either Traxxion or GP can fix your rear suspension just by giving you the correctly sprung and damped Penske or Ohlins rear shock. And both will get your front forks right with their own magic.