I've never fished for musky, but I often use a 10wt in the salt and occasionally for pike.
I've seen people attempt to throw some pretty hefty streamers, but for me that's not only not much fun, I feel it's overkill
In my opinion, you only need so much size to attract the attention of a large game fish.
The largest I go now is a 3/0 deceiver of about 7-8"
That's a mouth full for any fish, salt or fresh, and a hell of a lot easier to cast all day than any 12' dust mop.
For pike, I tie them in red over yellow and all black
I the salt I use all yellow or chartreuse over white
The simpler the outfit, the more skill it takes to manage it, and the more pleasure one gets in his achievements.
--- Horace Kephart