I apologize if I have confused the situation by throwing too much information at you. I work with paints and finishes and abrasives all day long and I'm pretty passionate about it all.
The last thing you want to do is add anything more to what is already there. You can reduce the shininess by using compound and then wax to abrade it. It may seem counterintuitive that waxing something will reduce the shine but that is exactly what it will do in this particular instance.
I really encourage you to go back and rereadmy previous posts and then get hold of some of the Tamiya compound and see if that does not work for you. It is also possible that if you have a cream type toothpaste, not a gel, it will do the same thing for you.
I know this all sounds a little bit crazy but,if done properly, you will get a superior finish that looks like a new really doped plywood covered aircraft.
Cheers from NYC, Michael