I would top off the degas bottle when cold, there is not much of a reserve capacity like the gassers have. I'd stick with the Mopar purple stuff as I've read about some funky outcomes when people have used the "good for all coolants" to top off.
You can get the Mopar in pre-mixed or concentrate, if you buy the concentrate only use distilled or deionized water to mix(this goes for any coolant/engine nowadays).
I know closing off too much of the winter front and/or not selecting a defrost mode when it's cold the coolant temps will spike but your going even higher than when I'm towing 8K lbs in 90°F weather (I've seen 222°F coolant).
