Exact same size, and features, as the regular Klymit LWD, just constructed with lighter fabric. The Klymit LWD uses 210 denier fabric, while the LWD-UL uses 75 denier fabric, similar to what the old Curtis designs rafts were constructed from.
I would say that 350lbs number is a very top end number.
The Alpacka paddles would be an awesome way to go. I plan on doing some hand paddles in the future also.