To really simplify matters, all I do is cut the core out along with any bad spots.
Leave whole and freeze .... hard as rocks!
Or cut in chunks.
Really depends on what you plan to use them for ... for me it is mostly for hamburg hash or soups,
So shape doesn't really matter, as I just bring them from the freezer, and add the "ice cubes" to the mix!
Likewise, I don't mind the skins left on but if you want them off ....
... run warm tap water over the whole frozen tomato, and the skin will slip right off.
Couldn't be easier!
If you cut them up, you can freeze them on a cookie sheet or similar, so they stay separate.
Then bag the pieces after frozen. Makes it easy to bring out what you need, when you need it!