You are a bit early for that just now..well, Cove anyway.
Best bet is to get down at low tide and suss out the lay of the land so to speak, and then fish it 2 hours either side of high tide.
I tend to wait until the Mackeral come in during the summer before I would even consider fishing there. I use an intermediate line and sandeel/fish pattern flies, normally dressed on a Varivas 2600. I like these hooks because of the almost circle hook proportions, that protect the point when the fly skipps across rocks etc.
Fishing actually in the harbour can be rewarding when the Macks push in baitfish (rumours of the off bass too!) but fishing the "open sea" can be interesting, with small pollock and Coalies.
I have never fished the outflow but my understanding is that you would not be able to fly fish it due to the terrain/it being busy. However, if you have access to a boat, thats a different story!