That sounds pretty good to me.
I haven't practiced that yet. In fact, I haven't seen that style of hook kick practiced at all in the classes that I've attended.
If I pass my green belt test (whenever they decide on a test date) they'll get me started practicing spinning crescent kicks. When the time comes where I feel comfortable with it, I'll ask my instructor about his thoughts on a spinning hook kick. Since his attitude seems to be pretty liberal with trying different things, I wouldn't be surprised to see him incorporate it into our training to some degree.
Our training seems to vary to some degree. When I started, we did a good deal of groundwork, then we hit bags more, then we went back to traditional drilling more. Now we're getting back into more groundwork.
I don't know if that's a planned sequence, or if he's trying to see which style of training certain students respond to.....
It doesn't make a difference to me because it's all good training, but it's a pattern that I've noticed in our school.

Spinning crescent were a technique that we didn't do ,but sound pretty cool.Sounds like one of those techniques that is best used in a sequence of other kicks.Kind of like the hook kick was for me.By itself I wasn't able to lead off with it without telagraphing my intent.Being tall gives good reach, but also makes it hard to suprise your opponent. I found that my first technique (other than a side kick) usually wouldn't score.Just too slow getting started.I had to be sneaky.
The spinning hook kick was hard for me to use and not hit too hard.I never was able to use it much in class, but did use it some in tournements. Definitely a bell ringer.Yet another technique that I wish I had perfected a little more. In a sparring situation it's a reaction kick.Timing your opponents roundhouse and spinning off that givies great openings for the spinning hook kick.
Spinning hook kick is another kick that I would probably pull something if I attemted it now. LOL.

Keep training, mark

I agree.
I've been working on the spinning back kick as part of my blue belt techniques, and I find that it's much more effective and easier for me to do when it follows another kick, like a sidekick or crescent.
I practice it on it's own, but when I spar I always use it as a follow-up behind another kick. Seems to flow better that way.

Believe me, I wasn't half as good as I thought I was. Traditional Karate is much more enjoyable at this time in my life. I was pretty arrogant in those days.

Mark