i primarily use a flood table these days but i keep my moms in 3 gal dwc. i use net pot lids with rockwool, i keep the water level about 2 inches below the bottom of the basket. but i change my water levels at diff stages of growth simply cause once its full on huge it drinks a few galons a day and keeping it a little higher makes my life easier.
something to note for people doing dwc, is a misconception i had when starting. it isnt the act of pumping air to the bottom of your rez that adds oxygen to the water, its when the bubbles break the surface tention that oxygen is added. i point this out because i use simple air stones, but when the roots start getting huge they tend to wrap around your stones greatly preventing air from getting to the surface, even if you are pumping air into your roots you will start to see some drooping over time, signs of slight overwatering. i have since pulled my stones to the sides of the buckets, on my larger plants i will even put them on top of the roots a few inches below the water level so the roots cant effect the flow of air at all. just remember you need air pumping into your water, but you need those bubbles to get to the surface. hope that helps