Roald, I watched the video and was amazed that anyone would even try that and I mean it in a very admirable way.
However, are your clients athletes looking for the edge AND have run out of training ideas? I've used jump squats before but never with more than 50% of my max and personally feel that they do give you that variety you need sometimes. Yet, I'm not so sure if there isn't something else I could do relatively more safely, such as getting much stronger and seeing more weights added on a regular squat.
By your own admission, you've been training on this for a while (specifically) and I would say that you are conditioned by now to attempt this quite safely. I am sure that there are some out of your entire client portfolio who might be able to replicate what you did, given proper duration and training. Again, I need to ask how it would benefit them as the only time I see a golfer needing that kind of strength is if he needs to support himself from being crushed by a falling tree during inclement weather.
You do bring a rather unorthodox approach and having attempted jump squats of up to 50% max load, I personally haven't seen the cutting edge benefit it brings relative to the risk involved in performing it. I would be most interested to hear your comments about any injury, pains or imbalances you might have during this period you started adding the exercise to your routine. What are you currently doing for restoration? You are either one tough SOB or you have hell lots to teach us if you remain pain-free.