Doug, do you know offhand whether the Bills Balls print test would reveal the lumpiness caused by saturated inks used at gamut boundry that you referred to earlier, and whether that would be somewhat ameliorated by more patches than 1728?
No, More patches will usually produce a more colorimetrically accurate profile but will not materially change the rendering of Bill's Balls from ProPhoto. A portion of them are imaginary, and most of the rest, aside from the neutral colored ones, are out of gamut so will be rendered based on the profile software designer's chosen algorithm. It's pretty much arbitrary and you will see big differences between Argyll and I1Profiler amongst others. Even when using the same exact scan data to make profiles.
BTW, these differences are a principal reason for Andrew's video that "All Profiles are Not Created Equal." Profile s/w should create the Colorimetric portions of profiles very closely as that is well defined. But even there, some s/w doesn't conform to the latest ICC specs, etiher V2 or V4. In particular the canned ones that came with my Canon 9500 II and Epson 9800 are defective but in different ways.
That said, perfectly well formed, "correct," profiles can and do have very different ways of doing Perceptual intent and especially how they map OOG colors in any Intent.
There's not a right or wrong for these as it's not a measureable attribute. My preference is that imaginary and OOG colors be printed with some similarity to the way they normally look in a wide gamut monitor. These colors are also OOG for the monitor but, unlike printers, monitors have well defined algorithms for how these colors are converted and what color results. Monitors that are similar to the Adobe RGB gamut will show Bill's Balls quite predictably.
As background, I printed four samples in P and R out of LR and PS with what I believe an as well as can be done 1728 patch on a very smooth baryta coated almost gloss paper using DropRGB as the engine, I’m still seeing room for improvement with that test. (I believe some of these results could be from imaginary OOG Lab colors that are presently insolvable.)
Attached is an iPad shot of what I’m looking at. The pics on the other side appear excellent but just hoping to see all the Z can do.
Doesn't concern me at all. I'd be surprised not to see it. Especially on a wide gamut printer with extra saturated inks. Has nothing to do with how well it prints in gamut colors and it's really something that the profile software determines and what the programmer considered important. You will see very different results with different s/w.