If the font's kerning between en/em-dashes is too tight, you could do your F/R to remove the space before/after and replace with a thin space before/after.
With Helv. Neue, when the paragraph style is set to metrics when followed by certain numbers, it is rather tight. Setting to Optical for the style's kerning seems to alleviate that, giving a bit more breathing between the dashes: On the left the style is set to metrics, on the right is optical. Note that the greatest effect is the en-dash before the numeral 8. The em-dash doesn't seem to suffer this issue no matter the automatic kerning method. But that en-dash is tight against the 8.
