That's interesting. I often make a little chart like that and put it somewhere on the camera for easy reference, but it never occurred to me to place it on the spotmeter. In my case that's probably because most of the cameras I do this for are not ones I would use the meter with anyway; just sunnyy-16. But I do like the idea!
One potential improvement might be to make a thin curved scale instead of the table, and mount it directly over the meter's shutter speed ring dial. The actual labels on the scale would consist of the marked speeds on your shutter, but spaced to align to the underlying scale numbers that show the actual speeds. This is sort of hard to describe so I am not sure if I am being clear. But if it could be done, it would save one step in looking up the shutter speed setting since you would be reading directly off the meter the actual shutter setting to use.