I've detailed curtainwall and I"ve detailed window systems in commercial applications, hospitals, institutional buildings, etc.
People indicate that curtainwall is an easier material to seal to, which I don't disagree, but window systems can be effectively sealed to the air vapour barrier, using foam... I tend to return the membrane airseal inboard along the rough opening, caulk/seal it to the window frame, then specify low-expansion foamed insulation applied from the outside.
In fact, one could omit the rod and just caulk the inside joint for appearance, given the fact that the foam will probably seal the airseal membrane to the window.
Any comments.