Thanks for drawing my attention to the theoretical side of contemporary Gestalt therapy. Your post reminds me that my knowledge of Gestalt was acquired mostly in the '70s, which I suspect was before the authors you mention did most of their writing.
So I guess it's time I got up to date.
I hope, however, that you don't insist that somebody go the whole hog and be a "Gestalt therapist" before he can raid your corral for good ideas. What you call the "real business of therapy" can be done in more than one way. If that weren't so (for a single example), we wouldn't have two rather different-sounding therapies -- CBT and IT -- in an outcomes horse race.
In fact, I hope you'll take it as a well-earned compliment if a reasonably hard-nosed behavior therapist like me wants to steal some of your clinical methods.