Rich, I'm sure you've done your research and know what's what, and you can use whatever you want. For the sake of others here who might not know what these things are, I will give a brief explanation below:
Perlite and Clay are both dense. Basically like rock. However, if they are heated to a sufficient temperature in the right industrial process, they expand to many times their original size, while keeping their original weight, thereby becoming much less dense.
Expanded perlite floats. This is because it holds onto its air, so the pores do not fill with water. Some of the pores may hold some water. The trapped air may or may not exchange with outside air.
Expanded Clay does not float, as far as I know. It has pores that will absorb water. Is heavier (denser) than perlite but not nearly as heavy as clay or sand, etc. Roots will grow into it.
Vermiculite is light and holds water or air, but if you put it in a mix it will smush down to where it's useless. Perlite and EC will not. EC is more durable than Perlite, but also heavier. I don't recommend using Vermiculite for any purpose.
When I run out of the Perlite I already have, I plan on just using straight pine bark fines, with none of the expanded rock additives. They are OK but I think unnecessary and expensive. PBF plus maybe peat, some fertilzer, perhaps some lime to raise pH, should be cheap, relatively light, and work well.