Rocking cuts- bulkier the item is, the longer the knife I prefer.
Slicing cuts- similar to rocking cuts, the bigger the item (like rib roast,) the longer the knife I prefer. For very thin slicing cut, like geoduck, I either reach for yanagi/takobiki or the thinnest gyuto I have.
For chopping cuts- I prefer nakiri...or my 240 I have, because of weight and small belly is better than 210 and 270 is a little bulky
Breaking down meat- I prefer 210 because it is more maneuverable and more nimble. I suppose if you're break down something big, you can use a longer knive, but for me I never get to break down those big things.