Got my pantone huey today ($25 on ebay) and played around with it a little.
I don't think it needs any 3d-printed baffle or anything, just press it against the blade and measure.
The huey has R, G and B sensors, but the colors don't line up very well with the LEDs in my blade. I started with my PL9823 blade, and measured the red, green and blue colors separately: (I used a command called spotread which was already installed on my linux box.)
| R measured | G measured | B measured |
red | 653 | 251 | 0.2 |
green | 318 | 933 | 142 |
blue | 455 | 324 | 2512 |
I also measured my screen, and got 292, 274, 341, so clearly the blade is brighter than my screen. :)
I also measured yellow, cyan, purple and white, and the values where basically linear combinations of the rows given above, like you would expect.
I'm not sure why the blue value is so big, I don't think it really means that the blue is super-bright, because it's not really super-bright.
When I measured my simple string blade, I got 1408, 1192, 5351.
My LED adapter + trans-white blade scores pretty good: 1708 1235 6458 near the base, but only 313 102 1689 at the darkest spot.
Finally, the LED strip blade:
| R measured | G measured | B measured |
red | 1403 | 586 | 0.4 |
green | 723 | 1784 | 147 |
blue | 785 | 530 | 4420 |
I think that pretty much sums it up: LED strips FTW.