Hi - just went through this so am happy to share my experience with you. Its really hard to decide when you can't try them out. I bought a Grace Queen with the King extension kit and also a Grace Start Sight frame. I did not like the Grace Queen/King. The tracking system was not nearly as smooth as the Start Right Frame and the tracks are very fragile, I broke two just trying to put them on. When using the carriage, the Start Right was much smoother and easier to control than the Grace Queen. However, the Start Right only takes up to a 13" machine head, so that's probably too small for you.
If I had the room I would buy a Grace Majestic, which is like the Start Right (same carriage and track style), but with more bells and whistles. It only comes in a king size, which as to large for my room.
Also, the Grace queen was really hard to get level and "squared up", this may be normal for wood frames, I don't know. However, the metal frames seem to be a bit easier to set up and get squared and level.
I sold the Grace Queen/King frame. I will be selling the Start Right as well as I am upgrading to a Nolting Funquilter on a Hinterberg Stretch frame, which I hear is wonderfully smooth and sturdy. I don't have it yet, so can't give my opinion yet.
Given my experience, if I had the room, I would get the Grace Majestic in a heartbeat.
Hope this helps. Good luck and let us know what you decide.
Solomae