For the premix oil I use any good BIA cert. TCW-3 2-stroke oil mixed 50-50 with MMO both of which come from Walmart. Any of the Redline 2-stroke oils would be excellent, including the snomobile stuff.
The only 2-stroke oil I could find at the local Walmart was called Super-Tech, and I couldn't find any certifications on it anywhere. Is MMO proven for this application? My research also indicates that the TCW-3 rating only is not recommended for watercraft (water-cooled engines), where the NMMA rating is required. So do we best get the stuff for air-cooled 2-stroke – which probably run hotter; the stuff for watercraft – which probably run cooler; or something else (other than Redline). Or is there no data to support a choice and I'm over-analyzing and it doesn't matter anyway.
Let us know if you notice any change when you go to premix. My old 1988 RX-7 felt spunkier when I started using premix in it but it was an old 150K mile beater.
If you were doing the 50-50 MMO at the time, that could make a difference. It contains both toluene and xylene which are very combustible. Some 2-stroke oils contain other octane enhancers. The Super-Tech is 'pre-diluted' ("with what"? you may ask) to make it mix more readily with fuel.
What Pre-mix ratio?? IIRC, I've heard on this list to use about 1 oz per gallon, which is about 130:1. Most 2-stroke applications are somewhere in the 20 to 50 : 1.