I've been flying a 46FX with APC 13x4 on 20% nitro with OS F plug, mounted on 4-1/2 lb Katana profile, and the performance has been very brisk, very strong verticals. A model that's a pound to a pound and a half heavier would not be quite as easy to haul around, but thrust is thrust. My Javelin was just over 6 pounds (by half an ounce) with YS63 power. Vertical was not fast, but it was plenty high enough. Propped that with a 13x6 APC.