Hugul Idea/Questions

Hey I posted this on the Hugul forums and not many people responded, it's really small and it's not really like Sepp's Huguls so I guess I understand. What I'm trying to do is like a kind of water retaining woody compost pile, which is pretty much sheetmulching with bigger to smaller wood chunks. I definetely have enough materials, there's a really overgrown patch near our house, tons of green material, straw, and logs. Plus what I've been collecting, the only thing I'm short on at the moment is spanish moss, have a good bit but don't know if it's enough, and the mini-forest has little to none 3:.
I have a couple questions though, really new to all this, like actually doing it I mean, have read about it for awhile.
1. Palm parts? Are they applicable as trunks? And the hard parts that form on the outside and fall out, the ones that kind of look like a snake's tounge shape, are they wood or brown matter? That's a lot of questions in one.
2. Is wood brown matter? I know for compost piles you're supposed to keep 30:1 C:N, and the same is true for sheet mulching, does the wood affect the C:N ratio?
So yeah, I'm going to put a link for the imgur album with a simple diagram of what I'm hoping to achieve and a mock layout, keyhole attempt xD. It has measurements, I read that 8 by 8 was good for keyhole size, what do you guys think about that?
http://imgur.com/a/SIWDd
Thanks.

"Is wood brown matter? I know for compost piles you're supposed to keep 30:1 C:N, and the same is true for sheet mulching, does the wood affect the C:N ratio?"

As I understand it, Yes. The wood will tie up N in your soil. I add chicken droppings and grass clippings to my semi hugel beds that had a good layer of rotting wood and leaves below compost and soil. I had no problems with lack of N. And the rotting wood did a good job of holding water. I had an excess of tulip popular, perhaps the best wood I know of for turning into a sponge at least in my area.