I would like to propose %sq = Sequence file name.
Could use this at the beginning that way all the targets, (including flats and darks), can be grouped under the same directory:
%sq%ft%tn%tn_%el_%fe_…
While you could create a directory for your sequence and point the location there doing it these way means you won’t forget each time a new sequence it created and run.
Cheers!
Phillip