I like Jay's approach. Does time always allow for these beautiful methods, not always. Worth consideration.

As for the wrap and strap in the video. I don't like the 2x framing on the outside of the t and g. It will be a bugger to get sealed when fitting all the pieces of foam into these spaces. Instead just wrap the sheathing in 4'x8' foam sheets and apply strapping to the outside of the foam with panel screws.