There is a whole class of typefaces optimized for high speed, low cost/low quality printing, which pre-compensates the letterform for expected ink bleeding, so called Ink Traps[1][2]. They are highly optimized for a specific printing method, the font size and the paper-quality used, and don't translate well to non-ink based printing.
The problem with current desktop publishing fonts is that they can't possibly be optimized for every single use case on screen and for all of the myriad types of printing so robustness while maintaining legibility is key. Especially if the product is expected to be photocopied I would always go for a reasonable bolder weight, uncondensed typeface rather than losing information.
Also make sure the 8 is distinct enough from a 6 [3] (Times New Roman beats Arial by lengths in this aspect)
[1] http://en.wikipedia.org/wiki/Ink_trap
[2] http://designmind.frogdesign.com/blog/calculated-errors-the-...
[3] http://www.dkriesel.com/en/blog/2013/0802_xerox-workcentres_...