If you want the info. from Dan's study, it would be best to get as much info. about the study, including how it was conducted, etc., directly from Dan. Personally, if I wanted to know how much weight it holds, I would determine how accurate it is, based on various factors. One would also need that info. to determine how many (if any) of the Clerks one sheets that eMovie sold were the alleged repros. In this case, I doubt that eMovie took highly detailed photos, measurements, and everything that would differentiate the alleged original from the alleged repro., if they are that close.
You also have to wonder how important it is to have an alleged original alleged versus one of the alleged "very good" repros. If they're that close to the same, is it that important to you? In 50 or 100 years or whatever, are people really going to look at the work that Dan allegedly did to determine which is the alleged original and which is the alleged repro., and are they going to put a significant premium on one or the other?
In this case, getting signatures on it might make it less desirable for people who prefer mint originals, and if you decide to sell it at some point in the future, it may not matter to a lot of people whether it's an original or a repro. A lot of people who are into autographs get items based on the autograph and not whether the item that the autograph is on is an authentic original or not.
Like I said before, personally, I wouldn't worry about it. I also wouldn't spend 10+ times more for something, from Cinemasterpieces or anyone else, for the sake of buying it from someone who supposedly has information that is not readily available to the public, but that's another topic.