Can't comment on the TC's, but I've got a lot of days on my Katana velcros--nearing the end of their second sole--and I wouldn't say that they've stretched that much. Certainly nowhere close to a full size.
FWIW, I measure 45 on a Sportiva brannock and wear a 44 Katana. Toes slightly curled, semi-performance fit, but still comfortable enough to wear for a few hours without desperately wanting to rip them off.
If you size them down they will stretch 1/2 size with ease of course the looser they fit the less they will stretch..
I have 3 pairs 39.5, 40, and 40.5 after breaking them all in each one is just a little looser than the other. I would say 40.25, 40.5, and 40.75 if that makes any sense.
Thanks guys, Worked out great. Amazon had them 1/2 size smaller for 80 bucks, but just size 43? Not sure why. I'm sure they'll work for just another pair to have.