Container question for coco grow

I currently have 24 plants. All are definite power plant f1 hybrids that should mainly be blueberry crosses. I am currently in small cups and it is nearing time to transplant into their final containers. This is not my first grow but the previous grows I had too few of plants in a large closet to worry about container size and just used large buckets. This time I am in a 4x4x6 cab and will be using coco as a medium. Does anyone have an idea as to what pot would best suit my needs and future uses? I have heard some say 1 gallon per foot of growth which seems overkill and others sizes that seem entirely too small. Any help would be greatly appreciated.