Take the advice of the dudes with pics of ten foot pikes before me because I've never hooked anything that big lol. But here is my humble advice:
If you're going deep use a willowleaf spinner blade size 5-6; for medium depth use a french or indiana spinner blade size 4-5; and if you're planning on bulging the surface (my personal fav.) I'd recommend a size 4 Colorado blade. Casting spoons work great and surprisingly so does casting flutter spoons meant to troll with. The erratic action is fantastic IMO.
Bright colours matter in medium and shallow depths, not so much after 15-20 FOW. I like green and yellow chartreuse, flame red, orange, and neon pink. If you can find a spinner or spoon that has these colours and a decent amount of reflective shine you're in the money. Just get your lure noticed, whether through obnoxious colours or wild vibration.