#1 This is called confirmation bias ed (or a rigged experiment). You successfully proved what you intended to prove.

#2 There CAN BE a change in cheek position with changing leading arm position. Leading hand just in front of the trigger guard forces the head forward, raising the eye and as if by magic you are now looking down the rib. How much is highly dependent on one's cheek weld, or lack thereof if the head is lightly in contact with the comb.
Do you believe you can reproduce that mount and comfortably swing the gun with your hand in that position?

BTW what most U.S. shooters did, unlike the Brits, was to crawl the stock to compensate for 3" DAH

[Linked Image from photos.smugmug.com]

[Linked Image from photos.smugmug.com]

Note the leading arm position of both