That makes sense! Thanks to everyone for the replies. I don't care too much about looking bloated for a while, but will definitely get a good travel pillow. (Hopefully this forum has some recommendations, will search!)
I'm about to book surgery with Dr. Lorenzo and have been emailing his clinic various questions. One of the things I asked is how long I need to sleep in an upright position and they replied that there is no need - I can sleep "normally". Has anyone else heard this from either that clinic or another one? Everything I've read says to sleep at a 30-90 degree angle for 5-15 days (the numbers vary from source to source).