If your main goal is to catch a rainbow, I have done well catching them on Memphremagog, Caspian & Echo. Especially on Caspian and Echo, I use 6lb flourocarbon leader with #6 or #8 hook, thread a live crawler the length of the hook and up on the line over the knot. I fish 2' - 3' of water along shoreline and lower the crawler to the bottom with no split shot. I like to fish near trees that have tipped into the water or near streams coming into lake, you might lose a fish or two in the snags but you will catch fish. Not difficult to catch rainbows with this method.
I have caught some nice rainbows on Memphremagong fishing with smelt just under the ice while fishing for salmon, browns and lakers.
Have fun and good luck.