I totally understand why you are trying to get rid of hydroton. I tried doing same few different ways, currently I am doing it just the way you described, 5'' net pots with only neoprene disk at the top.
I cut of small portions of net pots so the holes would be bigger and also holes in the lids are a little bit smaller than 2'' so that net pots wouldn't fall in when the plants get heavy. This works perfectly for small plants but I am not sure how it will work when plants get bigger. I plan on growing each plant to cover around 2.3x2.3(70x70cm) under 180w led and I hope they yield 200g. So we will see how big of a plant can this system support.
Btw, how big did you plan your plants would get? I think that is the most important question here.
Following you have photos how my setup looks at the moment. It is great for now, but plants are just few weeks from seed and i hope it will work when they get bigger.
P.S. Sorry for the photos being out of focus...