Quote Originally Posted by OneClick View Post
I've only stacked top quilts, a 20 and 40. It was a ridiculous puffball of down. Felt like I could have gone to -20°. Maybe more since my 0° alone was plenty down to -16°.

Good point about compressing the UQ. It would definitely be a good idea to test the fit before actually doing this.

I tried it years ago and it looked like a mess, but I think it would have worked just fine (don't over tighten ends like this)

Next time try stacking your 40* inside your 20* inside your 0* TQs. That should be enough insulation to keep you warm in the cold vacuum of space.