I forgot to mention, with the Poor Mans Tilt Test, get your assistant to note down any symptoms that you feel and at what point, e.g. say sweating, pulse in head, dizzy, etc..
If at any point you get chest pain or tightness, or serious dizziness – abort the test.
Regarding the bed position, many people chock the head of the bed, I’ve also heard sleeping ‘head up’ at 45 degrees mentioned. Rather like someone with a heart condition when you think about it!