Thanks for reply. That is the general understanding I have from reading his articles. I did not think / realised he recorded vario readings. I guess I was after more specifics, how long has he flown for a particular speed, did he need to correct for altitude, temperature etc. Did he made the calculation from altitude loss in kts, etc. Basically I am after the "method" section in his technique. I recall him writing about three tows to 10000 ft, which may point to quite long legs at a particular speed.

Cheers

Paul