Thanks for all your comments everyone.
David; I've found that, of course, when I put plants like Cattleyas in a net pot, the roots come out all over. But, when I put a Phrag or Paph in a net pot, I rarely find a root that I can see through the sides. The sides of course, allow lots of air in and the outside layer of potting mix dries out faster near the sides of the net pot. So, the plants roots grow well; but, they find the perfect distance from the wall of the net pot to position themselves. As long as I maintain a regular watering style, or regimen, the plants can plan for that by locating the new root growth at the correct distance from the inside walls of the net pots. So, in effect, I'm using a 6" net pot; but, the plant keeps the roots in a tight ball deeper inside the pot. I could probably pull the plant out and easily replant it into a 5" pot without squishing the root ball, because the plant naturally keeps the roots about 1" in from the walls of the 6" net pots. That's where the perfect balance of water and air exists to make the plant's roots happy.
I have a really nice, awarded Paph. haynaldianum. I did really poorly with it for a long time. Finally Wendy got it from me and she revived it in her warm, tropical basement grow room. Eventually, I got the plant back and again, it began to look unhappy. Then, I put it into a 6" net pot, in a mix of 1/2 perlite and 1/2 fine grade CHC. I hung it up where it got high light and lots of air movement. I also began watering it almost daily....at least on sunny days. It's grown and grown and clumped up beautifully! It's bloomed many times, at any time of year. It also finally produced a stem with 7 flowers this past summer, the most any haynaldianum has ever produced, the same number of flowers it had when it was awarded it's AM/AOS. I crossed one of the flowers with helenae 'Charlie' in the summer and the capsule took. Now, there is already another flower stem about 8" up out of another leaf fan. Even though this plant has been in a 6" net pot for a couple years, I cannot yet see any roots through the sides of the net pot. They are all staying inside, at what the plant must think of as the "sweet spot", where the mix of moisture and air is just perfect for it's liking. It sure is performing terrifically for me. That's something it never did when I grew it in a standard plastic pot. So, I'm putting all my plants in net pots (recently, I bought a bunch of cases of varying sizes of net pots from 2" up to 6". The small ones will be used for epiphytes and the larger ones for semi-terrestrials. True terrestrials like Cyps and Bletillas will still go into normal pots. I have very good humidity in my greenhouse and I mist/spot water daily. I am definitely NOT a dry grower. So, this method works well for me and I'm producing some of the nicest plants I've ever grown.