Most new riders under-use the front brake (or don't use it at all) and over-use the rear. Due to weight transfer you'll probably find the front brake doing most (but often not all) of the braking. The only time I use 100% front brake is when my rear wheel is in the air (or close to it). If you're skidding your rear tire then you probably should be using less rear and more front brake. I personally find dragging the rear tire down a downhill to be bad form (and it erodes the trail).
So: get your weight over the rear, use both brakes, and search for the braking limit on both brakes. You'll likely find yourself doing much more braking with the front than the rear.