Outriggers where designed for top water fishing. Typically used to pull a "spread" teasers, and baits out and away from the boat in an attempt to attract then entice the fish to come to the surface to feed.
I used outriggers to troll two additional large parachute baits (up to 8 oz.) per side but they are cumbersome and not easy to use in that application. If you get hit on the outside clip, you must bring both lines in to reset the outside clip.
If your looking to try your hand at lake trout or salmon you would be better off saving your money to buy a good set of down riggers.