I hope your tomato's bear well. The last time I planted seeds from store-bought fruit, I ended up with tomato's the size of a pencil eraser. There were a lot of flavorful little itty-bitty tomato's, but they all could fit in my cupped hands ;)
Yikes...had a hybrid Juliette mater plant last year produced a lot of small ones too. I'm hoping these 'store bought' tomatoes from seed produce bigger.. we shall see. As a backup I will purchase 2-3 other variety plants. Next year I gotta, gotta go with heirloom tomato seeds although cherry maters are pretty hardy against the heat. So many 'maters, so little room.