I've discussed that with Greggy too. His doubts are qualified by his own admission that he's stating this from an ocean away. Why do you suppose that his opinion hasn't transformed into outright advocacy in the same way Waterbury and Halkides have done?
You'll have to ask him that. I'm only really interested in his take on the knife evidence, which I think is particularly significant because he otherwise believes them to be guilty.
This is akin to saying my scientific opinion is valid because I put on a lab coat and peered through a microscope a few times. I will let real scientists take on Waterbury about his allegations regarding the forensics but what evidence does he have that RG was a police informant? And what is the source of his other allegations?
I think Mark Waterbury's qualifications somewhat exceed putting on a lab coat and peering through a microscope! He certainly has far more knowledge on the science of the case than I do, and than the majority of us here, so for that reason I'm looking forward to his perspective. The fact Mark and Chris's (and others') qualifications are attacked on here is, I believe, because people simply don't have the scientific knowledge to attack their arguments. Much easier, then, to attack the person or their qualifications.
The problem with your statement about other scientists challenging Waterbury with regard to his take on the forensics is that, well, none of them
have done, have they? The posts from Greggy I quoted illustrate that point: even scientists who believe Knox and Sollecito to be
guilty think that the knife evidence should never have been admitted. Personally I'd love to read a discussion between scientists who have opposing takes on the knife evidence. Trouble is, there aren't any scientists advocating the opposite take to Waterbury. In view of that, I can't see any way that the knife evidence will survive the appeal(s).
As regards Mark's take on Rudy being an informant, well, that's a different issue of course. It's certainly interesting that Rudy appears to have been caught by the police multiple times, yet never arrested. Apparently the defense wanted to include evidence that he was involved in six separate crimes in the weeks leading up to the murder, but weren't allowed to admit it because it's not directly linked to the case. But anyway, that's a different discussion.