Walt, I would say not far enough.
As I listen, especially with the background in mind, being part of the totality of the piece, every nook and cranny is being used up and thus in my opinion defeats what you are trying to accomplish. I'm thinking you need to work the tracks so that sound cuts, both in the background and foreground, work hand in hand with one another. You stated: learn how to keep "space" in my music, and not fill up every nook and cranny with melodic harmonies or interesting counter-rhythms, which doesn't seem to be the case, unless I'm missing the point of something here.
A lot of the background sounds work great with the foreground instrumentation but should also be in with conjunction with what you want to accomplish throughout the piece.
You thoughts on my thoughts!!
Peace and Blessings, John