Huh - I'll have to peruse sway's to see if I can find anything. Like you say Matt, it looks like they "inject" fiberglass into the foam to create the flex characteristics.
Not to worry Daniel, what's a little thread hijack among friends.
Are you having difficulty on the broadcast? That should be an ok board to learn on. What's your wake like and your position on the board?
One thing that folks tend to do when learning is dropping the rope too soon, which shortens your ride time. Getting your surf legs is mostly a matter of mileage. Just try getting slack in the rope, if you have slack, you're surfing. However, if you slow down, you don't have to start all over...get back into the pocket and focus on developing slack in the rope.
After a few sessions, you should be able to surf your entire run with slack. At that point, you don't need the rope and the broadcast should be an adequate ride for you for awhile.