I've got around 500 plots planted with tomatoes. Double that number with fertilizer added and it gives me around 1000 tomatoes to harvest every 2 days (or 40 hrs if I'm keen). It's given me more than enough to keep production of tomato sauce (via the preserves factory) at sufficient levels to service the needs of the pasta restaurant. In fact I'm building up a bit of a reserve of tomato sauce. I've still got enough tomatoes left to have 15 days worth of supreme pizzas on the go.
I don't use tomatoes for the sandwich shop though (tend to focus on pb&j's and tuna sandwiches there), so as others have rightly pointed out, it's all about making choices. Kinda like real life in that way