I would suggest going back to your usual haunt of the USA to obtain your Multi engine rating. At the end of the day you'll have plenty of practice flying IR conditions in the sim and the real aircraft when you come back.
Like you said you will at least have the weather. It might even be worth paying the extra to get a few more hours of twin flying in.
I did my multi-engine about a year before starting the IR and had no problems in getting back into the swing.