Re: However, in this case, it’s just a matter of what is most likely to be true on the basis of the best evidence available.

Ok, now that is a different tack as opposed to the open and shut case or a smoking gun approach elsewhere on the thread. As I see it, the available/presented evidence makes it likely that Hillary had a Smiths on his persona when he reached the summit, possibly the only watch he carried to the summit.
I am not all convinced if he was the first person on top and whether we can tell with any degree of certainty what Tensing was wearing. The evidence I am considering is the grainy pictures with mostly off angle view of watches, the letters, the claims, the ads, the 'admission' etc. The only thing I am discounting are the vehement assertions made on what I consider is thin circumstantial evidence for the claim that there was no Rolex between the pair on the summit.
BTW, I am sure you know where the picture is from.