All carbon is about 200g/mtr^2.
With tow cloth it's not easy to achieve a perfect squares as seen on this pic.
Squares with a stabilizing binder between 6-10mm Carbon 12K Plain Weave 195gsm x 1000mm = $25.94 / mtr in year 2014, Australia ( Dirk, I suspect you do not want to buy from here:)
It must be rolled for shipping. All irregularities on this pic are because of folding
The epoxy is Araldite K3600. First time using it and very happy with 70min pot life on 25C ambient temp. But, post curing is a must. I did post cure on 60-80C for first 5 hours, next 5hrs on 45C. After 10hrs done (was done after 5hrs, but the specs says posturing on 40C for a week will give maximum epoxy properties). The wood core (or a closed cell), must be sealed for this application if post curing on 80C temperatures. Otherwise, the project might be ruined.
The mast, of course, will float. I am already building a shorter one, with a Nomex Honeycomb core (a sandwich build tho, similar to this one). Expecting 350grams weight for 500mm length