Size of containers for hydroponic grow

I’m gonna grow 4 autos and I was wondering about the container I put the water in. Does total volume only matter or is a wider or deeper container work better? I was originally thinking a shallow container that was really wide would allow roots to spread out more And make a bigger plant, but that was just a guess. So total volume or shape or what really is best? I’m making my own set up but don’t have a lot of space or I’d probably just go with 5 gal buckets n call it a day.also I’m gonna try a get away with just one air stone in each container

I have grown and am currently growing RDWC and I use 5 gal food safe buckets. There are 7 gal. but I have had no issues with volume.