If you haven’t used any fuel systems cleaners in 81,000 miles, it’s time. I don’t know about your piston ring theory, but over 81,000 miles there is almost certainly carbon buildup on the pistons and CC’s, plus your injectors and intake valves could use a cleaning.
Without any information to back this up, I would think that a higher top ring would actually result in less build-up on the ring. If it were lower, the trapped, unburned fuel charge would seem to be a source for build-up. This is just how I picture it in my mind. What actually happens might be entirely different.
My current favorite fuel system cleaners are Redline SI-1 and Gumout Regane. There are many others. Get ‘em at your favorite local auto parts store and use as directed, e.g. add to tank (when parked next to the gas pump), fill it up, and drive until it’s almost empty again. Despite its stellar reputation, Techron doesn’t seem to work as well as the above. Fuel Power seems to be more of a maintenance product than a quick clean-up product. Some people recommend an oil change right afterwards (e.g. do it before your scheduled oil change) but the jury is still out on this one. If your rings are halfway decent, you should only get a minuscule amount of cleaner or byproduct of the cleaners in your oil. You get blowby in your oil all the time, are you worried about that?
Do you have reason to believe your rings are not sealing well? Bad compression or leakdown? Oil comsumption?