You sir have hit the Million Dollar question!!!
I've been fishing the Lake my entire life now, I've come to realize 2 things.
1. It def beats working!
2. It a total crap shoot!!
I know over the years some spots tend to hold bigger fish, where others don't. I keep trying different methods, presentations and combo's to try and figure things out. My log book looks like someone was using it as a coloring book. Between hardware, flies and live bait all seem to produce fish. I find the bigger fish i catch during the spring do come from live bait. Although there have been somedays i've had to use streamers due to high winds and a hefty salmon chop.
i remember reading a couple years ago about a marine biologist who was doing a study on the Salmon population of Winni, Said that the bigger fish tend to hover over the deeper trenches in the lake. I don't know if this is a complete truth, since i read on this website about the guy in Gilford pulling that 27" 7 lbs off the dock at WYC. Of course that was April fools day too, Could just have been a pretty good story.
Well anyways, Good Luck Let us know if you find the answer to your question i know were all curious