I will assume this thread is REALLY about the LEGAL cultivation of Cannabis, simply because so far there is nothing that has been posted to suggest otherwise. With that said, I also agree that the root mass would clog a NFT type system. Although personally I would also be very concerned about the root mass in 2 liter bottles as well. From my experiences growing the crop (unfortunately not legally, but about 20 years ago while in my teens and early 20's), the plant will easily become root bound, and then clog the PVC lines. I grew peppers in a two liter bottle flood and drain system, the pepper plants were only about 1 1/2 feet tall, the roots were already growing down into the PVC tubes and clogging them.
I'm sure you would have better luck using the horizontal 4 inch (100mm) tubing, and running it as a flood and drain. However I wouldn't expect that to be able to grow the plants to maturity either, simply because of how big the plants get. Even with only 2 plants per 10 foot long tube, unless you were growing inside and induced budding while the plants were about 3 feet tall. And you would need to create a system for top support of the plant, or it would become top heavy and tip over.
Personally, I would agree with Freshwater that you should really consider a
drip system. I wouldn't use anything less than 5 gallon buckets for growing a cannabis plant to maturity in myself. Depending on your specific grow site (specifically the vertical space), the only drawback may be the fact the reservoir would need to be lower than the buckets, in order for the
nutrients to be able to gravity feed back to the reservoir. However if that's not possible, that can be dealt with by using a much smaller secondary serge tank, though that's a little bit more expensive setup.