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.