I believe that I wrote that in my own way, we have a small sample of shots on video. I also believe that eyewitnesses who seen him play in the 60's and 70's are seeing a much different version of the man from the 40's.
In the clip provided by the OP does it appear that he is using a slip stroke? Yes or No.
Here is the link in case you missed it.
http://www.britishpathe.com/video/billiards-champ-entertains
oh, good grief -- the man is shooting wing shots in that video.
He shot masse shots too during his exhibitions -- because of that are you going to claim he used a masse stroke/grip for shooting 14.1?
Lou Figueroa