As you are measuring only 14 samples per cycle, you might need a different constant (not 1/1024) in the filter to maintain roughly the same time constant in seconds - or you might find that the ripple is more noticeable with the higher resolution of your ADC, so the original value remains sensible because it will give a (roughly) 8 times longer physical time constant which more than compensates for the increase in ADC resolution.
If you’re not switching the CT input from zero to half-scale (by plugging in a CT as is done with the emonTx V3), then you can have a much longer settling time because the d.c. bias should never move quickly, if at all. The only reason for the filter to adjust the offset quickly will be at start-up if the d.c. bias is not exactly mid-rail but the filter output has been pre-loaded to the ADC mid-point value.