A suggestion is to print inside the cover various information:

- Filter Factors for commonly used filters

- The arithmetic for using filter factors

- Bellows extension factors and the math for figuring it out

(Perhaps you could put a square shape on the cover that could be put in a scene just like the Calumet tool and include the math for measuring it on the ground glass to determine the extension exposure factor.)

- Reciprocity factors for commonly used films

- Arithmetic for combining multiple factors

That would save having to look at multiple sheets of paper blowing in the wind and would make the booklet very useful in the field.