Gagai and ChambersThey are both great players. But different skill sets.
The only way you can fit both is to have Slater at fullback and Boyd in 3/4. Slater in the 3/4 (wing) in Origin has been tried and was underwhelming. It's the last chance to see Slater, Thurston, Cronk and Smith together. I'd hate to pass it up.
We are so short on depth in the centres that Darbs at centre and Slater at fullback is a much stronger team than any other combo. Gagai and Morgan would be a turnstyle in the centres. Who else are you going to pick in the centres after ONeill goes?
To me, it's not about Slater v Boyd for no.1 . it's about what is the only sensible option for a back 5 - and that's Slater 1 and Boyd centres.