I'm feeling bad about being flippant before.
The clock trick, which I hadn't seen before, is fine up to about 45 degrees off the nose, with an error less than around 5 percent which is pretty reasonable.
If we start with 12 o'clock being wind on the nose (ie no crosswind) then each hour represents 5 degrees off the nose. Thus
1 o'clock = 5 degrees, multiplier = 1/12
2 o'clock = 10 degrees, multiplier = 2/12
and so on up to 45 degrees off the nose.
Beyond 45 degrees you can use a additional linear pro-rata figure to maintain an error better than around 5 percent.
For example, at 60 degrees, the multiplier becomes
= 9/12 + (60-45)/45 x 0.25
= 0.75 + 0.25/3
= 0.83
I still think that it is not worth the effort when the prayer wheel can be jostled quicker and easier for better data .....