NFT/fog would be a viable system, IMHO. I was just pointing out the potential problem with putting something in the bottom of your rails and the problem of roots daming up return flow. I added misters to the system as a cheap way to keep roots happy without having to step up to a 50 gallon rez. It was also my introduction to a poor man's aero system, and led me to research aeroponics.

You are correct that misters will not help to produce the fine roots you are looking for, and would not play well with the fog. NFT with added fog seems like a hybred system that would work.

I use collars only when using the EZ-clonners, but in the grow trays it's collars with net pots. The object is to support the plant, the collar will hold the stem till roots form. Then when the roots grow thru the net pot they are also supported there, so then there are 2 points supported and once the roots reach the bottom of the tray (as in my system) and form a root mat they are very stable. BTW in NFT systems, even with net pots, plants have a tendency to "lean" upstream, against the nutrient flow as roots are pushed slighly downstream.