RE: Could I Put Monokote in my HUGE gaps to lower flutter or eliminate it??
The lesson here is that messing up step A means step B will also be messed up, etc.
Taped or sealed, it sounds like a gap that big could still lead to hinge failure and an elevator blowing off. The elevator response will probably be sloppy anyway.
If you cut the rudder and elevators off, remove the wire joiner, and re-install everything properly, it's still a lot less work than crash repair. Or, it it takes 4 hours to save a $200 plane, you're making $50/hour. Take your time, get it right, learn how to make the next model easier and better. Fly knowing you're plane's in good shape instead of fearing it's not.
best wishes![8D]