This is it, what ever is comfy, the bed is too flat, and whilst I was on bed rest at hospital I was heavily drugged up but towards the end of my stay, I tilted the bed. But you get fidgety if you can't sleep and this really annoys my wife.
I'm supposed to sleep only on my back and I generally never do this, I prefer to sleep on my side.
I've spent time sat bolt upright before now with broken ribs as lying down is too painful.
Even if we bought a spare mattress for a spare bed we could put up in the lounge, it would still be too flat. I'm currently at 30 degrees.