The ancient rule was that you never used a gear that was an integer ratio for a fix gear. 48/16 = 3; an integer. This means that the relationship between your chainring and cog comes up exactly the same every pedal stroke. 48:15, o issues. 49:16 is OK. 52:17 is virtually exactly the same gear as 48:16; just far enough off to be not exact.
I haven't ridden a gear that high since I was a first year racer 40 years ago. Listened to the club vets and moved it down the next year and got serious. So I have very l;imited experience on intrger ratios. A little on a 42:21 but that was virtually all on major climbs. Harmonic issues at those RPMs wasn't happening!
Ben