I think you will find a vast majority of turntables, regardless of price, are going to be off 33.3 rpm a very small amount. Most likely a small enough amount to be undetectable by the human ear. IMHO an infinitesimally small variance from the ideal 33.3 does not affect the quality of the sound. On the other hand, wow & flutter, a constant variation of the speed, does easily affect the quality of the sound.
The point is, will adjusting your overall speed by +/- .05% make you system sound better? In my opinion, probably not. So I wouldn't worry about that. I would worry about a dirty pulley inducing greater wow & flutter though.
The point is, will adjusting your overall speed by +/- .05% make you system sound better? In my opinion, probably not. So I wouldn't worry about that. I would worry about a dirty pulley inducing greater wow & flutter though.