Below is a script i've been playing around with, it works along with tasker.
what it does-
forces cpu1 offline when the screen is off
ANY! but, ***make sure not to use it with a cpu governor that hotplugs!!!***
no interactivex, conservativex, or...
I can't find any instructions on how to enable the hotplug governor in Franco.Kernel nightly 13.
Franco has released an app which does this automatically, but I don't have a credit/debit card so can't purchase it. Apparently the release notes for the Kernel give instructions on how to do this...