For regular (carve) jibes, the topic of when to switch the feet can be a religious battle. I'm mostly exposed to a group that believes switching the feet when the sail moves (the step jibe) is better, with
maybe an exception when really powered on small sails, so that's what I usually do. But I know at least guy who does beautiful sail-first jibes even with large race sails. Both ways work, and there are good arguments for each one.
But in all the lessons I have heard and seen about duck jibes, the foot switch is
always late. Switching the feet too early in duck jibes is a common mistake, and will kill speed. I have proven that to myself many times. My wife has much more solid duck jibes - there's a good example at 1:50 in this video:
When I copy her style, which includes a very late foot switch, my planing-out rate is a lot higher.
We windsurfers are a funny bunch, always developing theories. We see someone do something a lot better than we can, but can't help thinking we know better than they do, even if they have been teaching windsurfing for decades, and made many popular instruction movies. I have developed tons of theories about new-school freestyle moves which most guys who can actually do the moves regards as crazy. I'm still wondering if gaining some weight would help me to jibe like Dave White in "My Way"