Three talls can work.We’ve got Tabs & Lobb. That’s two.
Tracey & Amiss are the backups without having to move defenders around.
No decent team has more than 2 big key forwards at any time and playing three seems to make us too slow and the ball comes out too easy when it hits the deck.
Considering that players need a rest on the bench and if you go one ruck, one forward/ruck and one key post and one sits on the bench you struggle in the air.