Brah,
Before you make your decision on who is to build your custom ukulele (i guess sometime in the future now that you have decided) I would play, feel and inspect as many different ukuleles as possible. Take your time and see what you like, see who you like then go their factory, shop, etc. and talk to the builder. See how they operate, smell the wood. Find out if they will be building it or someone else in the shop. Interview him/her and make sure you can work with them before you plunk down the deposit. If you can't work with the builder and the builder cannot work with you, what do you think you will get? Sometimes you just click with a builder and they hopefully will become your builder for life. I think this is the most important thing when considering a custom ukulele builder.
There is lot of mana that goes into a custom ukulele. Believe me. I have the utmost respect for any and all ukulele builders but there are some that are right for you and some that are not.
About 3 years ago I had the chance to meet David C. Hurd of Kawika Ukuleles. Whom I consider, used to build one of the finest sounding ukuleles that I had ever heard. I went to his house/shop in Hilo, played his ukuleles talked with him and thought we would work together on a project. I started the "I want" process about a year later but could not come to agreements on some issues. He wanted to build me a Kawika ukulele the way he wanted it to be not the way I wanted it. Maybe I should have listened to him , maybe not. But It just did not work out, I'm sure the ukulele would have sounded phenomenal but I just felt the mana was lost. So we parted ideas.
I had found another innovative builder before Kawika by the name of Andy Berard of O'kona Ukuleles but unfortunately he passed before I was to have him build my next tenor ukulele. Andy, I believe was to be my builder for life. I still own one of his concert ukuleles. RIP Andy