Hi, Pete,
we don't know because each duck has his or her own personality.
If you go with a drake, see if you can find one who is mellow. Sometimes people will rehome drakes that are low on the totem pole. I would not want a feisty guy.
I also would go with a smaller drake - a Runner, or if you can find an Australian Spotted, or Dutch Hookbill, because I consider size difference and duck mating is rough as it is - having a big drake on top of a Runner sounds like trouble to me.
And there are always exceptions.
As for introducktions, slow and easy. First, keep him quarantined till you at least have a fecal test on him to make sure he isn't carrying any parasites. Then have him in a pen next to the ducks where they can see each other but not touch. If things seem calm, start giving them some together time.
Anything more than a little poking or chasing, separate and try again. Give them treats at the same time to give them a happy feeling in each others' presence. And please let us know how it goes.
There is a Free Rehoming forum - you can often find drakes there.
But I would stick with smaller drakes for your Runners' sake.
