Thanks APHers, for your question!
From your friendly TG experts on the NBA Tactile Graphics committee, we have the following:
Yes, a ruler with only whole numbers should always be transcribed in UEB, even in a UEB-in-Nemeth-Context document.
And yes, retain use of numeric indicator for cylinders, beakers, and measuring cups. In our reading, this is consistent with the chart on page 6-3 of GSTG.
GSTG 6.5.1 indicates that "All number lines transcribed in Nemeth within UEB contexts must be enclosed within Nemeth Code switch indicators even though numbers may not be modified. This applies whether they are drawn or created using braille symbols."
Number lines are covered in GSTG under 6.5. However, rulers are covered under Measurement tools in 6.10. Because it is not specifically addressed which code must be used for Rulers (unlike in number lines) use the following basic guidelines.
UNIT 6, p 6-2: When no technical notation is present on the tactile graphic
(e.g., only unmodified numbers and/or letters as defined in the Nemeth Code), the tactile graphic should be prepared in UEB.
UNIT 6, §6.5.1, 3rd paragraph: All number lines transcribed in Nemeth within UEB contexts must be enclosed within Nemeth Code switch indicators even though numbers may not be modified. This applies whether they are drawn or created using braille symbols.
Let us know if this provides a clear and actionable response to your questions. 🙂