I want to know the answer to the following question:
What was the HRF used with to set fuses?
All the background I'm provided with is that "The HRF was soon joined by the Height/Fuse Indicator (HFI), this was marked with elevation angles and height lines overlaid with fuse length curves, using the height reported by the HRF operator, the necessary fuse length could be read off.". Is that enough to answer the question?
Answer: yes