I always use those bagged container mixes. Not potting soil, that is pretty heavy but the container mixes are light.
I don't have containers anywhere near as big as yours. But have tried tomatoes in containers many times. Many Cherry types grow into big plants. So one or two only in a container. I always use transplants. If starting from seed you really need to start tomatoes in a very small container. Like a yogurt cup or a paper cup. Later transplant it to your big container that it will be growing in.
