Can confirm, I had this issue as well. I managed to find pillows the right size, but locally so I can't really recommend anything ; plus, it has to fit your morphology, what works for me won't necessarily work for anything else. Do you feel some discomfort just by putting your head on the pillow?

I'd like to know, is it possible to reload that solar-rechargeable battery during the day so that it's all ready when you go to sleep in the evening? It would be pretty much a fool-proof way to get your breathing machine working in any situation if it's possible.

I had issues with the headgear as well at first ; I'm a very "touchy" sleeper, and I have trouble sleeping with anything touching me : a T-shirt, socks, even sometimes the blanket rolled up in a bunch can prevent me from sleeping. So, you can guess that trying to sleep at first with a mask and a hos...

I can confirm for the altitude, I live next to the sea level, yet I recently went on a business trip in more mountaineous regions and my machine adapted itself to the new situation without my assistance.