I assume Phil would immediately go to a back 4, which given our lack of top defenders and lack of a top midfield destroyer, would be our best bet. 4-3-3 seems about right given our personnel. Could go 4-2-3-1 as secondary option.
From the games I was watching, it seems like he always changed formations, I'd think depending on who was available. That shows he has no problem to adapt.
Another thing worth adding and why I have a lot of respect for him, is that he had the balls to bench Miami's best player last season when he was being a diva and a nuisance. That player happens to be one of the greatest strikers of his generation.
He got benched for the 1st time in his career, replaced by a 21 yo striker. It humbled him and when he came back, he scored something like 15 goals in 20 games. Don't put pen to paper in what I just said, but the ratio was impressive.
He would have no problem benching Davies, if needs to. Herdman can't, which isn't his fault. I'm on board with Phil.