Hi –
If you have 31 channels, I would suggest n_interpolate only up to 16 max instead of the default up to 32 … you cannot interpolate too many channels. If you have thousands of epochs, I would suggest leaving cv=10 or you could reduce it to 3 if you want to be more efficient. Leave kappa as the default or you can also try 0.5 to 1.0 since you only want to drop epochs when a significant number of channels are bad. Ultimately, autoreject should figure out what’s the ultimate n_interpolate, consensus from the array you give it. So it shouldn’t matter a whole lot as long as the “true optimal values” are included in the range you provide.
Mainak