I would be interested in the answer to this as well. In particular, I have wondered whether starting out in ketosis makes the first couple of days on a fast easier as it is being in ketosis that helps with keeping cravings down.
Well, OP, I'd say test it: get yourself some strips to measure whether you're in ketosis, start eating ketogenic, when you are in ketosis start wf, see how it goes, if it doesn't go well try again :)
What I've heard is that it's good to eat as clean and as raw as possible for a while before a fast in order to build up the vitamin/mineral stores and in order to get the body detoxing gently so that the detox symptoms are not as hard during the actual fast.
I'm interested in how this turns out!