Really, I think there's going to be aggression no matter what when introducing a male to a female. There just is. The trick is getting the right fish so that the aggression is short-lived and doesn't cause any damage or unnecessary stress. If your female is 3", get a male that's around 2"-2 1/2". Make sure there's a noticeable size difference so the male cedes quickly, and stops the female from having to beat him up time and time again.
I'd acclimate him and plop him in, as long as I had a tank/bucket ready with cycled media and a heater.