I agree with Pat but what do you mean by "float bed," Grow 4 Food? Is that part of an "ebb and flow" hydroponic system?
I've said on here that I sometimes transplant tomatoes to 3" pots. Actually, I really prefer not to. The ones that often end up transplanted are the eggplants. Tender babies, unexpected cold weather keeps them indoors.
The pots I like to use are about 3" and square - 18 pots in a flat. The flat is the standard size, about 12" by 20".
Right now, things like this are in 4-cell inserts,
48 plants to the flat. Yes, it would be nice if they were given the room and living as
18 plants to the flat. But, what I'll be doing is taking
3 flats of plants and turning them
into 8 flats of plants! They would appreciate it but I have to find room for those flats

. (Also, that quite a lot potting soil . . .)
Steve
Edited to ask: And, what do you mean by "good ole' Prembrook For Seed beds!" I've long wanted to ask you

.