My idea is to build a large base that multiple pots can sit in. Currently my plans are for 6 x 1m trench style pots all sitting in a single large base. The problem with a drip or spray system is the added complexity of the sprayers and the fact you need to line them up with the plant. You can't just drop the pots in and out. (unless you are in a green house setup which this won't be)
With regards to the plants sitting in the fluid too long I have built a water sensor that connects to an IC and it turns the
pump off as soon as the water gets to the target level. So there wont be a long period the roots are submerged for - just the time it takes to fill.
Maybe deco would be a better growing material? Its also dirt cheap (sorry). Perhaps mixed with expanded clay to increase drain rate....