filter set to "low" pass filter (LPF)
crossover frequency tuned to ~80hz
crossover set to "12db"
subsonic filter (30hz) set to "off" if in sealed box, or if in a ported/vented box set to "on"
Gain setting is going to depend on your source unit etc. Learn to set gain via one of the available methods ( by ear, by DMM, by DD-1, by scope etc)
That would be a good starting point. If i remember correctly, those are all the settings on the 750/1 and what they are labeled.