Okay here are some pages from the Black Panther/X-Men crossover Wild Kingdom I worked on with writer Reggie Hudlin. I pencilled the Black Panther issues, 8 & 9, while Salvador Larocca did the art on the X-Men issues, 175 & 176.
This was one of my fave pages I did for the crossover, featuring T'Challa interrupted from hacking into the computer system, by a large, hairy armed assailant.
either way great work with the shadowing and layout!
You should be able to get Strathmore Bristol boards at any good art store, but try sampling different paper at the art store and see what works best for you. There are also companies that specialise in printing pre ruled blueline comic boards too.
Paper size is 11" x 17". Most artwork is usually kept in the 36.9 cm x 23.4 cm area, unless you're doing a full bleed page.