What size tomatoes? Are Roma tomatoes ok?

Yes, Roma tomatoes would work well in this tomatoes and eggs dish - which looks so tasty, by the way!

In fact, Roma tomatoes would be my first choice, as they are perfectly suited for cooking, and taste so good when cooked (much better, to my mind, than when they are raw).

For this recipe, I'd use 1.5 pounds of Roma tomatoes. You could probably get away with a bit less, if necessary. ;o)