There are different effects regarding 'lytic caps. First, they distort if they act as a high-pass filter, so you want your -3 dB to be down us much as you can -> use big caps.
On the other hand, bigger caps have higher leakage, so you might get to a point where bigger means scratchy pots and noisy switches.
There are some more subtile effects like DA, RF-pickup and series inductivity, which I think tend to get worse with bigger values. Although I must suspect that these are less important for coupling caps than for other applications.
If the coupling cap is inside a feedback loop, there is a good chance that you cannot change it's value without getting into sharp subsonic resonances.
As a rule of thumb, I try to choose the values such that my -3 dB point is below 1 Hz. There is usually no point in choosing a way-too-large value, better invest in a better brand. And use bipolar types where adequate.
Samuel