This watch was actually delivered in january but purchased by me in early april and I was not involved in the process, but the watch I had enquired with Kari was similar: white gold or platinum + blue enamel guilloche dial.
When I saw this for sale, I jumped on it! I seriously don't know what I would do different. The omission of the name plate really is an idea I love, but did not think of myself. After seeing this my mind was already infected by the design, and I felt a bit like cheating if I were to simply copy the design... Also waiting an additional 1,5 - 2 years for the truly bespoke piece made the decision easy
Regarding your question about process, my personal impression with Kari is that he is very open for ideas, but he can also suggest a few alternatives, so I would say that the amount of back and forth, really depends on the needs of the buyer.
I think believe that there are an article on SJX describing in detail the steps in a commission.