I'd say either in the position occupied by Gylfi or on either wing. Or, he's a sub. As I said, it means one of the four dropping out, or perhaps - in some scenarios - Gylfi dropping deeper, but I don't actually think that's the answer unless we're really pushing on like we did after Leicester went down to 10.
I'm treating it as a squad game, because we finally have a quality depth of players for those roles.
I think we saw v Palace how easy it is to target Walcott if he doesn't have space in behind.
I really like Theo and think he's a great player for us currently, but his skill is movement in behind and between the lines (the one chance he had came from quick passing and sharp movement from him).
So, the next time a team rocks up that's just gonna sit deep (maybe Newcastle), would it be worth trying Bernard/Richarlison on the right, with Walcott dropping to the bench?
You still have the pace of Richarlison and nippiness of Bernard, and since there's little space in behind, Walcott's sprinting ability wouldn't have as much of an impact from the start anyway, but we'd have him to bring on when/if the game gets stretched.