Garage Nut: Sorry I missed your post a few months ago. I have this same bandsaw machine.
For blade tooth density, it depends much on the thickness of the material you are cutting. If thin sheet, you want a very fine pitch blade. That goes for thin wall tubing square or round. The idea is you want at least 2 teeth in contact at any time. If the blade pitch is too course, you end up stripping teeth from the blade, as this overloads the tooth. And the harder the teeth, the more likely it is to destroy them. If the machine ever starts to hop while cutting, this ruins a blade in seconds.
Carbon steel blades are lowest cost, and general purpose for mild steel and aluminum. Stainless may require a better blade depending on hardness of the SS.