Should I attempt to add a capacitor to a power supply for outage stability?
Yes you can use a capacitor to cover power outages .It may not be practical for you .Remember that 1 Farad is 1 coloumb per volt ,this means 1 amp for one second for a voltage drop of 1 volt .If your power dip is not for too long like 100mS and your 48V 1.2 Amp load can tolerate 8volts droop then .o15 Farad will do it roughly .You could paralell 3 4700uF 63VDC electrolytic caps which is not expensive or exotic .If you need much more backup then lots of    Supercaps or Ultracaps in series will work if they are voltage balanced .