Mirrors, Mirrors, on the Ball

What's good and bad about Engineering is that there's something new to learn every day. The good is that it can be interesting; the bad is that it's hard work keeping ahead of the game. So I'm always fascinated to meet people with easy jobs, in case one day I wake up tired of challenges and decide to seek a change.
Which brings me to Tony, a recent bar acquaintance. I asked him if he was in Energy or Construction, usually a safe bet in Doha.
No. I'm a mirror ball Consultant. The only one in the Gulf. It's a niche market.
A what? Surely you just stick these things on the ceilings of tacky discos, switch them on, point a light at them, and forget about them till the next refurbishment? How little I knew.
I advise on the ideal ball diameter and mirror-tile size for the venue, the optimum x,y,z coordinates [sic], the correct orientation of the projectors, [I'd have thought pointing at the ball would be a good start?] Oh, and the speed and sense of rotation.
Let's get this clear. You travel around bars and night clubs in the Gulf sticking mirror balls on the ceiling. And that's it?
No, no. I don't touch them. I just give advice on best practice. I'm a Consultant.
Tony - drop me a line when you're retiring, OK?