yes, carbon fiber will be lighter, but more expensive. I used biaxial cloth when I did mine. here a quick overview of how I did it.
- Hull prep - grind off all of the ribs on the sides (i did this to my latest build, but not to my first one). makes it easier to lay the cloth flat. You can leave the ribs in if you like, but you will need to take more time to ensure the cloth lays flat over each rib.
- Fully sand the sides - I think i used 80 grit to really rough it up
- Cut your cloth - for the sides i used a progressively larger width cut to keep it strong on the bond line, but light as possible. 1st layer is a 3" - 4" wide strip cut the length of the bond line. 2nd layer is a 8" strip that covers the first strip. 3rd layer covers the entire side (again from nose to bulkhead) and from bottom to under the hood seal area. I used 8.9oz biaxial cloth. (i used about 12 clips per side on the hood seal area in order to keep the cloth from pulling away. i wrapped each part of the clip with duct tape to keep the clips from sticking to the epoxy.
I did the nose at the same time.
- Fill in the bond line/lay the cloth. I used 2-part foam on my 1st build, but used epoxy/hardener with west systems 410 micro filler on my last build. I'd go with filler not foam - When i filled in each side (bond line) i also wet out my cloth and layed each layer in, one at at time working out air bubbles, but did them all in the same session. In-other-words, I wanted the best chemical bond for all layers, tieing them to the bond line filler. I did not want separate layers, and bond line filler that were only mechanically connected.
I also reinforced the bottom... it was a long winter and I had nothing else to do...
as for coloring, I used Rust-oleum Marine Coatings Topside paint
http://rustoleum.com/CBGProduct.asp?pid=4 and it came out nice. not one problem with it so far.
Hope that helps. I would also search the FAQ section as I believe there have been a lot of write ups on this very topic.