UPDATE:
I just did some testing with some Osram SFH4231s (940nm) and SFH4230s (850nm) and ...
With at controlled as conditions as possible:
| wavelength | min If @ 30cm | S @ 250mA, 50cm | S @ 1A, 2.7m |
| 940nm | <2mA | 98 | 10 |
| 850nm | 33mA | 5 | 6 |
Summary: the Wii Remote is more sensitive to 940nm, but can't focus it close-up (longer wavelengths tend to focus at a greater distance for the same optics, so this makes sense).
S was measured using the full output format as documented at the WiiBrew Wiki