I'm using a combination of PVC stands, Fiberglass rods (Tap Plastics), & Sakrete Hydralic cement (Home Depot) for my 450 build.
Thanks for the input I also thought about using PVC, like 1/2 inch instead of rods to connect rocks, but the rods are so much smaller.
I've seen some killer PVC stands in the past, but I think I'll skip going that route for now.