Max, if you wanted to target trophy bluegill, use six-pound-test or lighter, a #8 or #10 hook, and either live crickets or live red wrigglers for bait; if you use worms, hook them only once through the nose. Fish with as little weight as possible, and experiment with fishing both on the bottom, and a foot or two off bottom by way of the smallest balsa float you can find. If the lake has a good-sized flat close to deeper water anywhere on it, especially if there is some weedgrowth on the flat, that would be a good place to look. There's a lot more to it than this, but this should get you started.
If you were already thinking of stocking tiger muskie, I would encourage you to do so. There's a hatchery in MN, Minnesota Muskie Farm, that ships anywhere in the U.S., and I believe they also deliver anywhere but I could have that last part wrong. They sell 10-12" tiger muskie. You would only need 2-4 per acre, and they would thin out those small bass in a hurry. And the bass that didn't get eaten would start getting significantly larger.
If LMB are the main focus, you probably should stock more forage for them, either more bluegill or perhaps threadfin shad (I don't know how they would do in WA, or even if you could get them up there). But if you have some interest in bluegill skip the shad as they'll kill the bluegill size.
One more thing you can do to improve the lake: start a fertilization program. It sounds like the lake is not overly fertile; fertilizing will boost the food chain and jump-start the growth of the bluegill and bass both.
Good luck! Take pictures and keep us posted on your progress!
