To me it looks like Veg Tan, with a little sunlight on it , then could have had a finish coat of something applyed to it.
what weight ? hard to say ,it could be 8-10 oz
My belt are cut 10" longer than the waist size.7" form the waist size hole on the billet end ...3" on the fold on the other end. After you get more proficiet you might go a little shorter.
Cousin Steve, glad you have found us.We will be looking forward in seeing your leather work.
if you get to Ludlow say Hi to Cousin Ray Hatley for me.........