I've been wondering ... is it best to de-click before or after decoding SQ/QS into 4 discrete channels?
Before pros: A cleaner source file that can be reused as decoding scripts / techniques improve. Only have to remove noise from 2 channels instead of 4, saving time.
After pros: De-clicking before may do strange things to the phase encoding for matrix surround. It's may be better to decode something minimally altered and then process in later stages.