What makes a good customer?

So, I am likely going to be getting a local superb luthier to make me a ukulele. I have some basic ideas. Tenor, would like a wider neck to accommodate my hammy fingers, and most importantly I want the best sound possible (if there is any question of sound vs decoration).

He has good design sensibility, so I'm comfortable turning the rest over to him but wondered if y'all had any suggestions for how to make a smooth interaction?

Thanks!