IMHO, you're partially correct, and your Dad is partially correct.
You're correct that you should only release the working
jib sheet when the
jib begins to luff, because up until that time, the
jib is still driving the boat, and, when you tack, you don't want the boat to coast, without power, any more than absolutely necessary.
Your Dad is wrong in his opinion that you should release the jibsheet immediately after the start of the tack, but he is absolutely correct in his thinking that you should pull in as much of the new working sheet as possible, by hand, before the sail begins to fill on the new tack.
Assume, for the sake of this discussion, that your crew includes one person to release the old working jibsheet, one person to tail the new working jibsheet, and one person to grind the
winches.
Depending on the size and type of boat, you might have to pull in 30-40' of jibsheet during a tack. It's easy to tail the jibsheet when there is no load on it. Once the
jib fills on the new tack, you can only pull it in by grinding the
winches, and that takes much more time, it wears down your crew, and it takes longer to bring the boat back to a close hauled course.
The person who releases the
jib has to make sure the sheet runs free, without any hockles, foot-
cleats or butt-
cleats.
The person who tails the
line on the other side should pre-wrap the
winch, and take up as much slack as possible before the old working sheet is released. Upon release of the old working sheet, the tailer should gradually take in the slack until the bow of the boat crosses the wind. At that point, he should start taking in the sheet furiously. When the
jib starts to fill on the new tack, the person who is grinding the
winch has to bring it in the rest of the way.
The helmsman can help the tailer get in as much of the sheet as possible, without using the
winch. As the bow of the boat crosses the eye of the wind, the helmsman can steer the boat directly to windward for a second or even a second-and-a-half, to give the tailer more time to sheet it in by hand.