Keep in mind Patterson (7' 4") and Gimlin (6' 1" or 6' 2") differed by over 12" on the guesstimate for the height. Krantz thought the film subject to be 6' in height.
The stride is measured from the heel of one foot to the heel of the same foot. Not impossible to duplicate. I'm 6' in height and have laid out the reported stride length of 81.5" on the floor and tried to duplicate it. Matching the stride length isn't too much of a problem for lanky people, but duplicating it with the bottom of each foot perpendicular to the rear with each step makes it more difficult. If you watch the film, the subject doesn't appear to be stretching or exaggerating its walk, which makes the stride length (if true) puzzling if no Monty Python gymnastics are involved.
RayG