So i just ordered my Warbonnett Blackbird DL and i was wondering if my summer down bag (REI Down Travel Sack 45*) could be slipped between the layers as insulation rather than a pad? (i also have a synthetic travel sack if that would work better??) not sure if this would work as my weight will "deloft" it????? but was wondering if anyone has tried and if it works better than slipping a sleeping pad under it??