The best fix for heavier motors, plus additional weights, is to replace the outboard bracket with a full flotation bracket make out of composite materials. It should be buoyant enough to compensate for a four stroke engine, the kicker motor, plus another 100 lbs. for either the live bait tank or a cooler full of ice sitting in the cockpit.
Fiberglass with Coosa Board 32 core would be the ideal materials to use. Stoner boat in Miami builds such brackets. Pulling the engine and swapping the bracket is not that hard a job, and would be a huge improvement. An aluminum bracket would also work, but if keeping the boat in a marina having a fiberglass bracket would allow you to use regular bottom paint, not copper free.