In your situation I'd consider going after the DD escort, then the Fiji, and then the transport.
If the sheep are unguarded, they can be taken at will.
Fast movers are hard to hit, so you are forced to take them quickly and split your torpedoes between the two DD. I'd send one after the nearest, after getting as close as possible. Immediately send the remaining bow torps after DD #2 and swing the stern. If you miss (assuming stern tubes) the second DD can have some of your ASS farts.
