Connaught because he was the one to get him in the position ? If anything, this would tie those 2 together, strengthening Connaughts situation.

But even if that's not the case, he won't be strong enough on his own, and this means he'll need to stick very closely to someone, and that would probably be either Munster or Connaught, either way, not a prefferable option for the 2 other dukedoms...

Anyways, this is my personal opinion, and it'll be up to my duke to decide..