@99Tjadams Yeah, the measurements I posted are of my specific pair of 21oz 555 SBG. I have some others I can take measurements of, but they’re mostly 14oz (though no stretch). My 17oz SExIH 633N have been repaired by Rain after a serious blowout and I haven’t quite rebroken them in yet, but maybe that will work to get me a better idea of what enough space is in the top block.
I may end up needing to do something other than 777 and then sizing down, but my actual waist is almost spot on 37 so I think I should roll the dice here and if anything, ask the IHUK team to look for a pair with larger thigh/knee measurements.