When to send save the dates and invites

I’m in a similar boat, just finalising out booking atm, actually thinking as soon as have invites created sending the to our priority people as we have 20 rooms set aside and we want those going to certain people. After that the sooner people book rooms better as if they’re precooked with out guests instead of generic hotel guests that seems better. I know you normally don’t send them so far in advance as your list may change but not sure how to balance that and getting rooms booked early! It’s hard isn’t it