I think this is a great idea, and does explain why different racqets with the same number of strings and different head sizes play different.
Vantage 95" 18x20 = TSDV 113mm
Vantage 95" 16x19 = TSDV 123mm
Vantage 100" 16x19 = TSDV 134mm
Head Speed Pro 98" 16x19 = TSDV 118mm
Head Speed MP 100" 18x20 = TSDV 123mm
I would say the control of each racquet directly correlates with the lower TSDV value.
TimothyO well done on coming up with what seems to be a good way to measure density rather than the stupid number of strings.
Incidentally I'd love to know what the TSDV is for a Wilson PS 85" which is always described as open but I think its not as open as most new racquets.