In relation to the Nicolai’s, which I would also recommend. I have a medium, but I I was speccing or looking now I’d get a large. In fact if speccing new I’d go large top tube, med seat tube. The reasoning is I like to run 760 bars and a 50mm stem. The TT on a med is just shy of 23″, the large just over 23″.
On my med I have to have the saddle further back on a layback post than I’d prefer, I’m 5’10.5″
Either fits fine, the large has about 0.5″ higher seat tube, same stand over.
I echo other comments on the bike, just works, great, love it, mashing gnarr of pedalling. mine is 31lbs with a hammerschmidt, 12mm Maxle rear and dropper post. Easy 29lbs 1×10 or 1×9, 30lbs without a
I’ve raced mine in a number of SuperEnduros and done 75mile a day hikes across the lakes, takes it all in it’s stride.
Speak to Rich at gravity sports if you want to look for one s/h or new.