Bigwideland:
Hi,
What is more comfortable for you?
For me it was on my right, side.
Also being propped on my back up is becoming more popular at 450 plus.
i am the same as you - mostly on my right side, with some pillows to help support me. when i turn onto my back, i need to be propped up a little with those pillows.
one of the things i really miss from my thin & fit days is being able to sleep on my stomach... as well as how easy it was to flip from one side to the other back then!