-11c
-5
bargain and wide
you don't need to worry about weight and size unless you plan on walking with it, so wide ones are really good as you can move in your sleep, they pack down well into stuff sacks, get stuff sacks, that have reducing straps on the outside, so it easy to stuff into a big sack, which can then be made small, small stuff sacks are so annoying and hard work,
I also have herdwick sheep skins (joined end to end) if you sleep on these, I have mats below, it's not only comfortable, but you lose no heat downwards, they last a life time and look gorgeous.
never store your sleeping bag in a stuff sack store hanging up, and they work better,
and when you are camping, get them out to air any chance you get hang over car,line or branch, the more you air the more they puff up, and the moisture you sweat is evaporated, so the sack will stay warmer at night.
long silk underwear under your PJs will help, layers are always the answer,
we each have a very light fleece blanket, very light weight, cheap, warm, and wash well, so don't care about them being abused,
I have double silk liners for our bags which also add a very warm layer.
those £4 fold up tartan plastic back picnic mats(tesco or pond land), good base layer to any bed, followed by self inflating mat/silver backed carrymat sheepskin, and you won't be cold.