[sdiy] VCO Accuracy

[Tom Adam]

A noob question about VCO's...
How accurate does one calibrate a midi 2 CV unit (+/-0.001V)?
How accurate does one calibrate a VCO? (+/-1Hz)
I understand that the accuracy is limited by design, but what is the 
"allowed" deviation before our human ear detects the error?

I'm about to calibrate a MOTM 300 & 310 and an oakley VCO. Although I've 
tuned them after building I'm looking to get all 3 of them in "perfect" 
tune.  Is there an easy way to accomplish this?

Thanks,
ToAd