Hmmm... a couple questions for you...
- What type(s) of kingsnake(s) are you trying to breed and how big are they?
The breeding size of a Scarlet Kingsnake and a Mexican Black Kingsnake would be different... you get what I mean.
- What is the ambient temperature in your room?
You could stop heating the whole room and just use heat pads for those that aren't being cooled. But you'd need to get your room's temp to like 65F or lower. (Some people don't cool their kings at all.... you could try that too....)
As for the time, I have some of my larger kings already cooling and a few that I am trying for the first time will get their last meal at the end of November. I plan to bring them all back up to regular temps sometime around the middle to end of February. Some people will put them down for 4 months and others for 1.
I hope this helps or at least makes sense. I've been up waaaaay too long.