glenb.
I agree, it's an excellent technique but (unfortunately) not widely taught. If you go horizontally from the wind vector until you hit the vertical centre line you can do the same thing for head/tail wind component as a fraction of windspeed.
Then divide the groundspeed by 10 and you have the distance flown in 6 minutes.
Sooooooo easy. All solved and not a wizz wheel in sight.
HFD