I've just started doing this recently actually.
I'm only going to do it for about 3-4 weeks max, then back to once a week for a bit. I'll see what happens, but i'm in the latter stages of a diet right now, so i'm not expecting miracles. But my refeeds are more frequent right now, so we shall see.
I'm doing direct neck training x2/week right now also. Just getting into direct training but after 3-4 weeks i'll do once/week probably.