I want to capture a photo of my SpyderCheckr in sunlight conditions. I know I don’t want the sun shining right on it. Should I set it up so that the sun is slightly behind it? Is it useful to also get a photo of it in the shade?
I don’t think the sun shining directly on it is a problem. The important thing is that you aren’t in the reflected zone–so if the sun is at a 45° angle, you would stand anywhere except on the opposite side at a 45° angle.
For me, it was useful to get a photo in the shade on a clear day, since that represents illumination from blue sky. I’d also suggest cloudy sky, night, and twilight. You may also want to get multiple sunlight shots, for example 6500K and 4000K or 5000K. The time of day to take these depends on your longitude. But for me, having more than one daylight photo has diminishing value, since… is this for darktable? Since in darktable I noticed my 6500K preset is very similar to the 5000K preset except the illuminant color and chroma. The major value you get from a calibration profile is the channel mixing settings, and those are similar for the different sunlight calibration photos.
If you create some presets, you can name them like “night|twilight” and “night|evening” to have them nested, so you don’t have to worry about having too many.
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Yes, especially if you plan to take photos under those conditions. Personally, I would take one under green foliage (eg under the trees), as I often photograph under those conditions. It will overcorrect but then you can dial it down.
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The big thing is to avoid glare. If that means you underexpose that’s ok, as long as you capture meaningful signal, that is, well away from the noise regime, for all 24 patches, especially the ‘red’, ‘green’ and 'blue ones, as they establish the gamut extents codified in a matrix.
Unless you’re controlling it in a studio, ascribing a single color temperature to a scene is a gross oversimplification. I personally just use a D65 profile for most of my serious shooting, as it’s usually in outdoor daylight, and the distinction between direct sun and skylight doesn’t disturb my sense of color consistency, even when I get a chance to directly compare the scene to the render. When I decide I want to do better for a particular image, I just go straight to my SSF LUT profiles, heh, which are all D65 anyway… I might have to test that heuristic. 
Edit: Need to add the most useful treatise on the subject there is:
https://rawtherapee.com/mirror/dcamprof/camera-profiling.html
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There is some info here… PIXLS.US - Profiling a camera with darktable-chart PIXLS.US - Profiling a camera with darktable-chart
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