Suggestion You can easily make one yourself. Google “clock face clip art” and among the various image returns (usually will be one of the first ones) will be a white clock face with only the hour numbers showing. You can paste that into a text editor or drawing app, resize as desired, and put in the percentage numbers yourself.
12:00 100%
12:30 94%
01:00 82%
01:30 70%
02:00. 55%
02:30 35% (or 38% I have seen both)
03:00 0%
Just continue around the clock face with the same percentages at the appropriate hour markings. It will look almost exactly like the one you remember (which you probably saw in a YouTube video about wind aiming). You’ll find though after using this for a period of time you will have memorized the percentages and their relative positions and will no longer need to rely on the image.