[michaelborromeo]

Both.

I haven’t done any actual tracking but others have.

There are studies linked at the bottom of this article: https://www.bulletproof.com/sleep/sleep-hacks/inclined-bed-t....

[sandos]

I just this day realized that I did not have any head- or sinus-ache when waking up, and I had used a pillow for once.

An inclined bed would probably be even better.