Stonefish has the fly selection pegged. I personally like a small (size 10?) Muddler minnow as well.

Getting down is usually not a big deal with sea-runs (or any trout, for that matter), but weighting the fly itself is ideal in most cases. Unweighted buggers seem to work better off a sink tip (or with just a bit of split shot on the leader). For weighting buggers, I like cone heads (in black). They provide a "jiggy" action the trout seem to dig, and they get down fast. Whatever you do, I don't recommend using sink tips for trout. They're a bear to cast on light rods, and they affect your ability to mend your line once they sink, which is a disadvantage in trouty pocket water, IMO. A floating line never leaves me feeling compromised for trout fishing, except in stillwater applications that I don't use much. If you feel the need to get down further, split shot on the leader (or better yet, tungsten putty) will get you where you need to be. Especially with split shot, however, you will want to avoid hitting your rod while casting.

Have fun.