Also, if you do a constant flow system where you drop net pots into a gutter or other long narrow vessel, does anyone put media in between the pots or just in the pots?
I would think it's only needed in the pots but I haven't seen any cutaway pics of how people set these up.
Do you put media in between the net pots or does the water just flow through freely?
I don't know of a chart that describes pot size, but I can give you some examples. For fast crops like lettuce and leafy greens, I don't use any net pots at all. Just drop that starter plug right into the raft. I've even grown fairly large plants like kale in 1" square starter plugs. If you are using DWC, then the water will take the root mass with no media at all, and a deciding factor may be how large the stem grows. My romaine will completely fill a 1" square hole, so it needs at least a 2" pot. Tomatoes and peppers I would advise 4-6", especially in a greenhouse where they may grow for more than 1 year.
I've destroyed 'many' a 2" net pot letting Romaine grow out to full size (maybe 20-30% of the Romaine grown ends up bursting the 2" pot). Swiss chard as well, depending on how long you let them go for... especially if you've sown more than 1 seed per pot, and use the 'cut and come again' method... Chinese cabbage is probably better suited for 3" net pots as well...and leeks...
@Verna: are those dirt plugs in your AP system?
@Vlad: sounds like it may be more efficient to just use SOLO cups ... so long as they are cheaply available they are disposable and doesn't matter if destroyed.