Save money, do this:
http://hildstrom.com/projects/seafoam/
I have never used anything but Sta-Bil. No problems with any engine for a long time. For 2 cycle engines, I use either Opti-2 or Stihl 2 cycle oil in the mix, with the recommended amount of Sta-Bil. Since the only 2 cycles I have now are a mini-tiller and a chain saw, a 2 gallon can of fuel will last me a long time. The can of fuel I have now is about 3 years old (87 octane E10). It shows no sign of deterioration.
I, too, have certificates that I could hang on the wall. The B&S factory certification and the Tecumseh/Peerless certification have expired, but the Kohler has no expiration date.
I agree, a "chemical overhaul" just does not work on some carburetors!