Yes, you can make both caps switchable. This gives you relative flexibility to adjust the gain and distortion structure. Together with an input pad you can then react to almost any recording situation and microphone.
As Doug wrote, the BA2C has Champ genes and tends to overdrive with increasing input levels. That is an absolute plus of this negative feedbackless design.
Sometimes, especially with hot signals, this is too much of a good thing, so switchable caps can make the difference here. Listen to it and decide for yourself if it makes sense for you.
Of course, you will also lose output level, which is best compensated with a compressor / limiter.
The cathode caps can be switched almost poppless, if you connect a high impedance resistor to the capacitor in series.
