Just put on 4 winter tires and forget about it.
However, before, I have tried having only 2; both just on the front and just on the rear.
In my actual experience (I have a big, empty mall parking lot beside my apartment building), with only 2 winter tires, having them in front is better. Sure, you can oversteer in corners (fish tail), but control is quickly "recovered" by the front wheels "pulling" the car straight. When you understeer, you can also recover by the pulling the car with the front wheels. Another understeer recovery technique is you can pull the hand/parking brake to lock the rear wheels while at an angle; You'll induce a spin but before spinning uncontrollably, you again need to "pull" the car straight.
This is the main advantage of having a FWD car over a RWD. When a FWD's rear lose control, the front wheels can actually pull it back straight; If you have traction on the front wheels that is.
Having them on the rear only, it felt like having no winter tires at all. No advantage in braking (front tires do most of the braking). I won't even talk about over or understeering; You won't over or understeer because you're stuck and won't have a chance to do any steering at all! When your rear tires lose traction at an angle, you won't be able to pull/recover because your front tires don't have traction either!
As for brand / model of tires: I had more traction with old / already cracking Michelin Alpin Pilots than my current brand-new Hankook iPike RC01 or my other car's Nexen's. Psychologically though, I have more confidence (of not having flat tires in the middle of a snowfall) with my brand new Hankooks than my old/used Michelins.