Self Calibration and DBCON

Let's say you have two data sets that you want to DBCON together. Should you self calibrate them individually? or after DBCONing?

The tip I got is you should self-cal each data set individually as best you can, then DBCON. However, after DBCONing, there might be some small gain offsets between the two data sets. Do a final A&P self cal on the DBCONed data set with a really long SOLINT, so that you basically have one SN solution per data set. This will ensure the original data sets are as consistent with one another as possible.