Mask types for sleeping positions

Is, there any hard and fast rules as to which type of mask is better suited for a particular sleeping position? I usually sleep on my sides and use a nose only mask. I find that is moves out of position and leaks alot when on my side. I'm using a resmed ultra mirage.

I am a side/belly sleeper and use the Nasal Aire II which is a nostril mask. It took me a couple of weeks to get used to the hose up you nose, but now I love it. I have another regular face mask that I use for naps.

One thing that I finally bought that really helps, is a good Chin Strap. I got a good one from cpap.com and it is well worth the money not to have dry mouth.

Most of the time I wake up in the morning and can't even tell if the machine is on or working. It is just that comfortable.

snorlox, if you want only a nasal mask (covers the nose) and you sleep on your sides, I'd suggest the ResMed Mirage Activa. Amazingly leakproof for most people, no matter how you smush it against a pillow. And works best with the straps rather loose.

If you think you might want to try a "nasal pillows" interface, I absolutely love the Breeze with nasal pillows for side sleeping and tossing/turning.