I like the MT28, but I was thinking the larger size would allow for greater root development. I see people VERY GENTLY teasing young roots out of relatively small pots (or cups) at a snails pace. As a propagator of many varieties of perennials and woody ornamentals, this would not work for me. I have all kinds of pots, different ones for different uses, but the general idea of a tall narrow pot was what I was thinking of. I use Pro Mix BX and it seems like many people agree that you need to add more pearlite to the mix so that's fine. I would leave them in the pot for about 3 months, like a Spirea. Let them develop a full root system. No reason to rush. If you are scared to break roots you could snip the top of the pot on each of the 4 sides and peel it like a banana. Again, I'm not married to this pot or this vendor, but if someone else has a source for a similar system, I'd like to hear about it. It is the maximization of space and time that is the most important to me. And of course great tasting figs!!!
Oh p.s. I saw a tip about using fine or shredded pine bark chips to cover the top 1" of the pot. People say this is to hinder the fungal and gnat problems. Any thoughts?