the key is if the branch can be bent back on itself and survive, and you can find this out pretty easily by trying to bend any unneeded branch on the same or similar tree.
Refreshing to get to the actual answer here for me as well, as I use crushed brick exclusively as a substrate, and I expect it to act similar to a clay pot in CE exchange, (none).
many of the books and seminar demonstrations deal with "refining" or "styling" a tree that's been pre-destined to be a bonsai. This doesn't help beginners like you (or me) learn how to take raw material and start developing it. I suggest looking at books and seminars dealing with raw collected...
you live about an hour from Nature's Way (I live in Dover).
there's a meeting tonight (which I sadly cannot attend)
the Susquehanna Bonsai club has members from at least as far as Williamsport and West Chester, PA. These people don't make it to every meeting; I'm sure they prioritize and...