Hi Tarquin,
10,500 on a 12x11 is pretty good. What nitro content is in your fuel? As for running the Hanno parts in the longstroke case (no 'notches'), I am not convinced that the notches have much if any impact on performance. Interestingly, the Hanno MKII ringed version does NOT have the notches, yet the performance figures are the same as the 'ABC', notched version. I have not run my ringed Hanno, but my suspicions seem to be confirmed by your results. The notches are supposed to improve 'lugging power' (which i would call torque) in 2-stroke engines, but that is pretty vague and may be irrelevant at the rpms we are running our two-stroke 60s. I read about the 'notches' in my copy of the 'Two Stroke Tuners Handbook' which also contained the formula provided by Dag. Their application of the formula was to determine proper gear ratios in racing motorcycles.
I have never been a fan of square (12x12) or oversquare (12x13) props, as you discovered, needle settings and pipe lengths get more critical. The 12x10W prop also worked well for me and did not require needle or pipe changes from the 12x11.
Looking forward to hearing about your flight testing with the Beetle and seeing photos of the long-awaited finished model!
Regards,
Will