At least for me, I will tell you what is so comfortable, you gotta try it.
Sleep position will be soldier style, but you need a comforter blanket and a really fluffy blanket and a big pillow.
Use a little bit of the fluffy blanket as a low-head rest. Pillows raise your head too much. Use the pillow as an arm rest over your stomach. You can even choose to hug the pillow a little bit. Sleep under a comforter blanket.
Right now my mattress is an air-pumped mattress. This setup is so comfortable because my head is lowered and the armrest feels so much better than having my arms at the side. You must really relax in this position. Think about dreaming and just float away.
What do you think is the best setup?