You've got to be a little careful when Rich and Alden start working together ... they would leave Laural and Hardy speechless.
Rich didn't correct Alden on his 100% equals a full vent. He only corrected the mid-vent percentage. So, it does look like your logic makes sense:
100% = Full-vent
75% = Twix a full-vent and a mid-vent
40% = Mid-vent
Hmmm ... that means if Elliot built a mesh sail to be equivalent to an extra-vent, the designation would be something like 150%l!!!
In fact dugard, lamasters & I had that very conversation with Elliot some time ago and damned if I recall the outcome...insert comment here...but it definitely was a laughfest!
Anyway it's safe to say the first kite outta my bag will likely be the 75 first unless it is dead calm. On 50,75 or 100, 50s and a green race frame, it flies down to an oh so sweet float and slackline machine!
The 100 easily flew in the near steady 20mph wind that was WSIKF this year also with green race. Could easily have gone to 3 wraps or even fours if need be for even higher breeze but it was far too long to walk and I was just plain lazy!
Oh yeah......Alden who?