I think you want a smaller tent with a fly that fully covers it. Basically the heta that escapes your bag will heat the tent, a bigger tent means more airspace to heat. The full fly also helps hold more heat in and cold air/wind out.
Oh for sure, that's just what I have.
I have a different 3 season, 3 person, but the entire tent is screen material, with a rain fly that goes to about 2" from the ground, but is twice as wide as the tent. That somehow seemed like it'd be cooler.
"There are no finger prints under water."
Okay, climbed in at 12:00am. I think the initial heat of being in my house carried a long way. It's lightly raining and is 24 degrees. I boiled some water and stick inside a tall water bottle to stick at my feet.
I have the zero degree, cloth, Nebo bag. Inside are two of the reflective Z-lite pads. On top of the pads, but still inside the zero degree bag, is my 3 season, down fill, GoLite bag. I'm wearing fleece bottom and top, with wool socks, and a fleece cap with a neck gator. I have gloves, but not wearing them while on phone.
Getting in initially was very warm. Now that it's been almost 15 minutes, any part of me outside the bag is cold (fingers and one forearm). Any cold parts will warm up once covered. Now that my face and hands have cooled down, I can really tell how much heat this water bottle is putting out. It's just about uncomfortable how hot my feet feel right now. Regular house pillow. I'll report later.
"There are no finger prints under water."
Woke up at 6am, slept through the night just fine without waking at all. Temp readings inside the tent on the wall/ceiling is 41, even though it's frozen. Temp in the grass is 32. Water bottle temp is 92. Pretty comfortable night. Re-entry to bag/s went okay and everything is comfortable right away, except the pillow moved and now a frozen part is right on the back of my neck. So far things went very well.
"There are no finger prints under water."
Thanks, but the hunt doesn't start until Oct 19. I'm just tent camping in my backyard to work out the kinks and see what can be improved upon.
"There are no finger prints under water."
I missed that part, good idea to get yourself used to the abuse by sleeping outside though. I find the cold to be much more tolerable after you repeatedly subject yourself to it.