I noticed that a mistake is often made in this and other websites about IBT. Advice is often given about using the length of the bed to calculate the correct magical 5 degree angle. That advice is quite misleading. The distance that must be used is the distance between the legs near the head of the bed and the legs near the foot of the bed -- not the length of the bed. For example, my bed is 200 cm long, but the distance between legs is only 141 cm.
I used a CAD program to precisely calculated the required length of the legs at the foot of my bed, while retaining the original legs near the head of the bed, in order to achieve a 5 degree angle. I have uploaded that drawing as an image titled 'Bed Angle Calculation', in case it is of any interest to anyone else.
The bed is a Wenatex bed, in case anyone is wanting to modify that brand of bed.
I consttucted tdhe legs from 90 mm downpipe PVC, and the materials cosst about $ 20 AUS or about $ 15 US.
I have also (hopefully, successfully) uploaded photos entitled 'Installed Bed Leg', 'Bed Leg Assembly', and 'Bolt Through Slide-on Cap' to give more details.
If anyone wants any more details about fabricating the legs, feel free to send an email to firstname.lastname@example.org.
While I am here, I might also mention a clear-cut benefit of IBT. I haven't seen it mentioned eleswhere, although I have not read all posts, so I might have missed it. IBT helps reduce or eliminate gastric reflux. This is not hard to understand. Gravity moves the contents of the stomach down away from the inlet valve at the top of the stomach when a person lays down with their head higher that than their stomach.