You can not really use those dimensions, they are approximations only. And even if those dimensions were not approximations, it would be very difficult to measure the design accurately. More importantly, your stamps are not perf 11 x 11, they appear to be 11 x 10.5; this would make them the very common #632. (See image below as evidence that the perfs are different sizes.)
Please note that the 'rotary waste' stamps are incredibly rare, I think that there are 10-15 of them known. Chances of finding one is less than getting hit by lightning, winning the lottery, and dating a super model all on the same day.
The best identification approach is to always assume that you have the most common stamp since this is always the most likely situation.
Don
APS #094826
