Hybrid owner here!
Camped in plenty of 30 degree weather last winter and we stayed quite warm.
1. I cut out
Reflectix panels for all of the tent end windows/screens. The tent itself is vinyl BUT it is only canvas over the screens and cold air comes right through.
2. I made Reflectix blankets for each tent end. I took a 2 x 25 foot roll and cut it in half so I had two sections of 2 x 12.5. I then taped those together with Duct Tape to make a 4 x 12.5 blanket. I lay a reflectix Blanket over the tent end and cover it with a Brown/Silver reversible tarp. (Brown up to absorb sun and silver up to reflect sun).
I know it sounds complicated, but it is not.
This kept us warm AND no condensation on the inside of the tent.
We used one of the oil filled heaters (looks like a little radiator) as I feel it is safest with pets (two cats and one dog).
This kept us very cozy!!!!
One night in our travels it got real chilly and I was too lazy to get out the Reflectix panels for the tent windows. WE FROZE! We could not get it warm in the camper.
Packing now and Tuesday we leave to do it all again - Yippee!