Sounds like you got as much benefit out of sleeping at an angle as I did from my Earthing sheet.
From reading the reviews, it sounds like the gist is “sleep with your head elevated in relation to the rest of your body.” I don’t think I need to waste my time with the book if that’s all there is to it.
@derek, it’s been a couple of years since I read it, but, yes, that’s the gist of it. If you like, give it a try, it can’t hurt. You can use books or there are even boosters that you can buy on Amazon for the purpose that are quite cheap.