Well you are right and there should be more sizing info on the site. I am 5'11 and about 175 lbs and the Large fits me perfectly. The XL grades up 1" in length and arm length and down 1" for size M. All of these jackets are somewhat custom and made from a numbef of different highly technical fabrics. Ultrex, Gortex, andTomen are all used. The whateproof breathabiloity ranges from 6000mm to 20,000mm. All zippers are YKK and the front zipper is a heavy #8 while the other pocket and vent zippers are slightly reflective and waterproof.
One thing is for sure, you will not be showing up at at your riding spot with someone wearing the same jacket.
I rode in this jacket and was super stoked but don't take it from me. Ask Kafka at www.wowkite.com
or Anton at Colorado kite Force or Brian and Jake at Kite Utah/Windzup.
These are made in Oakland Califoirnia by our local factory who has made product for Patiogonia, North Face, Sessions, Four Square, Bamboo Curtain, Curves, Ibex, Ernesto etc. They have been making outerware since the beginning of the snowboard boom. It is pretty cool to see them back making quality stuff! Sorry China!