Only have a minute here, but I very strongly advise you to not look at mature trees, 15' trees, anything remotely like that until you have lots of experience with smaller ones and keep them going for a few years. Cypress would not be the first one I'd try in any case, let alone with no drain holes.

I do not use lava rock due to availability in small sizes but there are probably some sources. As to granite get chicken grit which is usually available at feed stores as well as some other sources. Sizes vary. Another good product is diatomatious earth available at auto parts stores such as NAPA used as oil dry. Turface is another good product since it is fired clay particles used on sports fields. In our area John Deere carries it.

The bald cypress I place in mason tubs LOVE being submerged for the first year or so. After they leaf out during the second year, I'll make drain holes in the tub.

Bald cypress, even the mature ones, are quite easy to make into bonsai. I recommend them to beginners.

I've put up a second video on what I did with that tree.

http://www.youtube.com/watch?v=HrdZ-5sDIdo

I'll have another video on how I pot freshly dug trees. I don't know how soon I can get it up on YouTube.

I am very interested in you methods for crushing lava rock. I just order it off the Internet. As for haydite-based soils, I make that myself.

I tried crushing lava rock myself, using a capped pipe and a steel pole, but I ended up with too much waste. Further, I still had to wash out the dust from the good particles.

Here is a link that might be useful: Bald cypress - Year 2 - Carving