Keep Warm in Bed
I don't like any doona which is even slightly heavy. So I've found the best, light, warmest bed covering ever - just unzip your sleeping bag and open it out flat. If you wish, put it into a doona cover. This will make a double-bed size 'doona'.
Its extremely warm and extremely light. If its a very cold night, you can put one, or even two, woollen blankets under it, on top of your top sheet. Flanellette sheets and pillow cover are also soft and warm.
I've found this to be very comfortable.
I have a Down filled Doona very very light and very warm--I also like to warm the bed with the electric blanket--heaven