I tried to do what you do Jen, and just let DD bf all night, or atleast had the boob out all night and she could get on and off as she wanted. (alot younger than yours I know), but I felt I didn't sleep well at all, felt I was always feeding her, because she would still wake me up when she started sucking, so it felt like it was constantly all night, when it probably wasnt...I get way more rest sitting up and feeding and then laying back down again when done.
amazing how one thing works for someone but not for others.