Eusebius wrote:
Problem - I'm overweight and snore. Worst on my back, better on my
side. But if I go to sleep on my side I roll over easily onto my back.

How about the classic solution of sewing a pocket into the back of your
jimjams top, and putting a tennis ball in it? You roll on to your back
while asleep; it's uncomfortable so you roll back on your side.

Better yet - have you tried losing some weight? I dropped 2 stone last
year and SWMBO tells me the snoring (and the rather alarming associated
sleep apnoea) has stopped completely!

David