I think it works well at St George's Hill (there are 27 holes surviving from an original 36) in that the third nine is very much a lesser course, suitable for those who might want to play only a few holes or senior golfers for whom the length and hilliness of the big course is no longer feasible. It's a relief course. So these thirds are far from equal.
Also a part-Colt course, Kennemer is a 27 complex. Personally, I did not enjoy the Van Hengel (A) course (which I have only played once) as much as the B-C course (which I have played several times), but I think there may have been work to the A course. If it's Frank Pont's work it should be a much improved course. I'd be interested in the views of Mike Clayton who has probably played the Dutch Open there on a course drawn from all three nines.
The Wisley is a fairly good example in that each of the nines is of roughly comparable merit. Whether you like the course and its style is a different matter, but of its kind it is good. The three nines at Princes are also pretty equal.
How about Burnham and Berrow, Sean?
I have been lucky enough to play Ridgewood, but not all 27 holes, only 18.