So after reading my original post I can see how it was a little silly...I guess basically I was asking what are the lowest temps which can still support these snakes eating and maintaining a healthy metabolism. I wasn’t sure the high 70’s were appropriate to avoid rotting food in the gut. I’ve since found a thread mentioning that kings will still eat down into the low 70’s and supporting evidence from some breeders who will still feed year round with some reduced temperatures in the winter. I friend of mine has also told me her milk still readily eats in the winter when her home temps are high 60’s-low 70’s. So problem solved!
I still ended up putting each on their own individual heat source just because I didn’t like the lack of control being all on the same cable. They’re running around 85 hot side now. I’m feeling a lot better about it and the milks seem happy.