@discobeard Hey man, no worries, for once I can maybe help
I took a 33 with these (this one falls on 33,4), I basically sized like I would have for the 21oz since it looked similar and also thanks to IHUK info.
I'd agree with Freeman who answer my questions just some post above that the fabric is a little more rigid. For the waist stretch that could be less we should trust him also since he has worn his jeans for a year straight
But imo this jeans needs to be sized similarly to the 21oz. I did not wear it much since it's too hot for the moment, but the heaviness/suppleness feels the same.
Take into account that the waist could stretch less than 1 inch as pointed out by the IH crew.
For reference I'm 1m80 and now 72-73kg approx.