I think perlite could be tricky because it's so light and expands a lot. Maybe not a problem once it becomes a single root+medium mass, but normally in a wider bucket the medium can both raise and settle easily.
I use hydroton in my netcups but also at the bottom of hempy bottles/buckets so they don't clog the drain hole and there's some more space for the res part at the bottom, drains/flushes easily. Main down side I see is that although it's possible to reuse hydroton, it does take more work to clean the setup for next round and more work to remove it from the root mass. One of the main things I like about my hydro setup is that I can harvest the plants and have the system cleaned and ready for next run within an hour.
I think the vertical post with 45degrees elbow combination could work very nicely. Recirculation with a medium, even hydroton, can be tricky, but also provide a buffer in case of a technical failure. A sprayer above each plant site (and no medium) could work too.
That would obviously add more work and probably maintenance, but check out the video below. I was looking for another video but this is even better, scroll to roughly 8:40 and watch a minute or so for this rather clever but simple solution that may still apply when filling the tower with hydroton.
Actually, google or search youtube for hydroponic tower for more inspiration.