With regards to 200mm of insulation with seven frames: I would make sure the insulation was sealing to the cover board - just to reduce the heat loss as much as possible. Nearly half the cover board will then be out of the equations, and that above the bees should be insulated anyway.
With just a frame at each end removed, I would not be so concerned (if the colony were strong) and just replace each with an insulated dummy - but I think full-width insulated dividers are the better option, especially if we are talking 'big nucleus' here.
Make provision now for feeding candy later.
One of the reasons for me going to extra deep frames was the better (perceived) wintering as a) each frame holds more stores b) the bees can munch vertically with less risk getting separated from lateral stores later in the winter (happened a couple of times, possibly) and c) bees are further from the floor for most of the winter (away from the OMF).
So my next Q is: are you using OMFs? If so I would consider restricting them a little if the colony is only nuc sized.
Regards, RAB
