I have worked with several pros - Colbert, Wadkins, Litzke, Elkington, Nelson, Couples and now Notah Begay III. Their "engagement" levels vary considerably, with Notah and Jim Colbert being pretty involved, albeit in subtle ways.
On my new project with Notah, he has walked (well actually taken what he calls "Mr. Toad's Wild Ride" with me driving.) While I did alternate paper routings, in the course of those trips, he twice said "we need to use that creek more" and "slide this hole over to save that specimen tree". Both suggestions (repeated a few times after the tour) were eventually incorporated in the final (for now) routing.
We also discussed overall length, and I got some pretty specific ideas for greens and general ideas for contouring (both dos and don'ts) Of the three routings, he also gave a general impression of the one he thought was best.
Now, I don't know how a Paul Cowley would add those percentages up.....I do the first 90% and Notah has the option of changing it near the end of each design phase. Is it 90-10, or does the fact that input comes at key times skew it more in favor of Notah? The same pattern evolved with Colbert and Colbert Hills, for example. I will also say that Freddy had input of zero. The others less than the 10% stated above.
But, I did learn something from each one of them, so they had some value to me personally. As Tom D states, I have gone through that mental gymnastics of whether I want the fee vs. my "principles." The results are what the results are, but that topic is best reserved for another day since I am leaving for my golf stretching right now, i.e., yoga.