I'm 174 with 80 inseam and ride a S/M size (the L is 2cm longer on top tube). I dialed mine (early Smooth hound = frame does not fold) like my gravel bike but a bit more aggressive (handle bar is 15mm lower).
last year, I rode the frame as a fixed MTB/flat bar gravel with a shorter stem (90mm), taller steerer, dropper post etc. and now I ride with a shorter steerer (40mm shorter, not shown on picture as I got raid on the big black spacer and 1 purple spacer), a 100mm stem with ritchey cyclocross handle bars (I had 110 stem and road short reach handlebars) and a carbon seatpost with 25mm offset.
in both cases, I ride with 165 cranks. I built a hammerhead 7 (suspension fork) with 170 cranks and I would not go longer as it would hit the ground in every corner.





Point I am making is that if you really want one of these bikes, get a frameset with a full length/uncut steerer. The difference between the 2 frame is not that big and you are at the limit between the 2 old frame sizes. Note that on the Japanese site, they don't seem to have 2 frameset size anymore, they use different stems to differentiate Size M and Size L.

These framesets are using very common standards size so you can fit whatever you need to suit your morphology and fitness.