I don't think there'll ever be more than 10 members.
10 strong members is enough, so they don't need a second ship and a lot of small fry.
They'll always only help them out temporarily and than be left behind as friends.
Having only a small crew is more personal and more fun.
"For Feanor was made the mightiest in all parts of body and mind, in valour, in endurance, in beauty, in understanding, in skill, in strength and subtlety alike, of all the Children of Illuvatar, and a bright flame was in him"