Thats great news Kaosb1964 !
All the things you have mentioned are pointing to a lean mix as you say.
I am of the belief that carburettor manufactures set a spesific float level for a very good reson, and any changes to it will affect its performance.
Ethanol is a great fuel and has some good points but it has two main drawbacks, firstly you need more of it to make the same bang and secondly it absorbs water from the air readily causing gelling with some premixes and promoting oxidation. By adding bio blended fuels without jetting changes you are effectively leaning the mix a little. Personaly I only run 98 octane or higher fuel in anything that I want to perform.
I too have noticed a marked inprovment in the engines problems after the carby work ie. it revs heaps harder.
I am waiting untill I get some new parts before I try to tune it any further, such as a new air filter to replace the torn one, new inlet manifold to replace the perrished split and possibly leaking one, some reeds to be sure to be sure and lastly a throttle cable to replace the worn out prickley and kinked cable that is on it. The next check will be the ignition timing.
All the obvious problems with the rev 3 i am working on are pointing to a lean mix like yours.
Ile know in a day or two if ive fixed it.
Keep ya posted.