Any conclusions, Ronnydog?
I use the marine version of Sta-bil, or Seafoam, or Startron.
All have left a layer of water at the bottom of the tank after 4 to 5 months of storage.
On the motorcycles, I have taken to running the carbs or fuel injection dry after shutting off the fuel supply.
Running the fuel dry prevents the gas turning to goo, but allows the 0-rngs and seals/gaskets to dry out. So o-rings may need to be replaced. Sometimes the newer o-rings will swell up to their original size when re-exposed to fuel.
Usually I fill the metal tanks full to keep the tank from rusting. On the TW with the plastic Clarke tank and the boat with a plastic tank I try to leave it empty.
In the past, I have tried emptying the metal tanks and fogging the interior. This works but is extra effort.
At the beginning of the riding season for me (mid April in NC), I drain the full tanks and put the fuel in my wife's car, a few gallons at a time.
Then I fill up with fresh gas.
Of course you could do like Qwerty does... make your own non-ethanol gas.