That would be ideal but unlikely as poster is in zone 5.If it will be well protected in winter I would leave it until next spring, when the buds start sweling cut it and repot the layer
I tend to think about this in the opposite way. It is all about the rate of transpiration from the foliage and the balance of foliage mass to root mass. Rather than focus on the roots (which are just starting to grow) I think it is easier to try to reduce the rate of transpiration from the foliage via sun and wind protection and misting. Then you don't run the risk of overwatering the new roots.As roots develop the tree will take more and more water from the new roots and there's a definite risk of the whole layer dehydrating if you don't keep up with water.