>>687320Some points to be made:
Is that temperature rating for the sleeping bags the extreme low temperature rating or the comfort zone?
Because in the first case the only thing that the sleeping bag will do is avoid that you die of hypothermia, you really want to look at the comfort zone.
Also, please invest in decent mat insulation, inflatable is fine but no big open cells, air will move around and create connective air movement, which is a very efficient way to transfer heat from you to the ground, so invest in a good mat with an excellent R rating.
Do not rely onto fires to warm up the tent, the tent itself doesn't keep you warm but it has the important function of avoiding windchill and weather in general, but in cold weather be mindful of water condensation on the inner wall of the tent.
The best thing you might to is to do some light exercises before getting into the sleeping bag.
Also very important, eat a proper meal and pee before getting into the sleeping bag, you'll waste a lot of energy trying to keep all that water warm, also having to pee at 3am when it's freezing is a terrible experience.
