Brian,
Here's what I use in my 14; I think you'd like it :
http://www.cabelas.com/stools-chairs-seat-cushions-primos-double-bull-qs3-magnum-tri-stool-1.shtml
You can probably find it a little cheaper (think I got mine at Bass Pro at around $30 ea.); but in a 14, two of these seats will easily fit side by side for two hunters, and they are VERY sturdy. You can collapse them and throw them under the shelf when not in use (they even have a clip that holds the legs folded tight) .
The BIG + is that the
tri-leg setup makes it super easy to stand and shoot when the time comes. A 4-legged chair in a TDB 14 makes it harder to shift the leg over & back when you stand because of the extra room it takes. This type of stool makes standing to shoot very easy.
I have a cover-up/rain roof I designed for my TDB, so I flip it back when I stand to shoot, but even using no roof I'd assume you stand to shoot.
Nice shot on East Fork!