Try mounting a small bubble level just below the gunnel next to the seat. I've ocassionally found bubble vials (without any frame) sold as keychains. If carefully mounted where visible from your paddling position the level vial makes trim adjustment a snap. Just move your daypack or whatever cargo you have backward or forward enough to achieve level trim. If running into a substantial headwind trim bow down slightly, if running with a strong tailwind, trim slightly stern down.
Marc Ornstein
Dogpaddle Canoe Works