Something you might consider -and if you do, it's essential that you do it before they begin building- is to get the prep for Series option. I'm not sure of the current price, but I don't think it's too bad -Mica or Susan could tell you.
This option would allow your bass to be upgraded to Series at some future point. They drill and shield the cavities, I think they install the 5pin jack and the dummy humcanceller, but most importantly, they build the body just slightly thicker -which is necessary to house the Series electronics.
If there's any possibility you'd like your bass to be upgradable to Series at some future point, you should consider this.
I'd strongly recommend considering a Balance K body as well; it looks great and is incredibly balanced and ergonomic. To my knowledge, they've not yet done a Brown Bass in that shape.
Congrats, and good luck with your custom, which will undoubtedly be... well, an Alembic.
Getting L.E.D.s?