In general 25:1 or 4% is the baseline for old school aircooled 2 strokes.
Engine desingers use percentage numbers like 5% or 4% oil.
Dyno runs may use as much as 8% or more oil.
This is what I use with the HT after reading Gordon Jennings & Graham Bell's texts on the subject of 2 cycle lubrication.
20:1 with mineral oil for the first 2 tanks.
Then quality synthetic at 30 to 1 after that.
More oil is more power with these old tech 2 strokes.
http://www.bridgestonemotorcycle.com/documents/oilpremix6.pdf
40: 1 or leaner will lead to seizures and or fast wearing of the rings/cylinder on these air cooled motors.
Modern watercooled 2 stroke engines speced for using synthetic oils are another story...
40:1 is common
Thats where the confusion starts.