I'm not really sure that whacking crosses in to Toney, in itself, will make the slightest difference – it would be very predictable and the typical Premier League central defenders will eat them up and spit them out. Goals seem most often to come from set pieces and/or quick and unexpected actions.
Whatever formation we go with, the number 1 priority is a strong and stable defence, that's the current problem – that defence must be strong against width (so not Thompson or Canós) and quick to react to balls threaded through centrally to quick runners, more like Ajer. Currently it takes an age to get the ball forward because the players that can do that are either unavailable (Henry, Raya, Ayer) or not on the books (a RWB).
To make Toney effective, we need the ability to get wide but, more often, the ability to get quick balls into the channels and react to them... then to get players around him, either to pick up lay-offs and second-balls or benefit from the distraction his presence causes. That's only going to happen (assuming we have the players) if all the other players aren't firefighting in our own half.