Bill,
My wife and I have been paddling Quetico for 35+ years in July and August. About 20 years ago we switched to a queen size down quilt instead of sleeping bags. We just use it like a blanket. We also use a sleeping bag liner that my wife sewed up using cotton sheets so that we are not just laying on our thermarests. 1 quilt and 1 light weight liner is a lot less weight  and bulk than any other sleeping bag combo that we have looked at. Much cheaper also and never been cold. We do use bags in colder weather.
Good Luck.
Gene.