Nice looking plane Mark I to used the Dubro glass gear ,while it works good it is heavy. After doing some checking around the other day I happened to measure the gear on my GP 60 sized Extra 300 S and its almost the exact same thing as the glass gear offered by Dubro only its Alum and less than half the weight. I can see a set of these in my near future, but I don't fly the plane often its one I like to take to shows and so forth.
One other thing you mentioned was your paint not being quite as shiny as you would like, I dont know what you used for paint but in the pics it looks to be a good match and heres a helpfull hint you may want to try out.
Good old Wally World has a cheap brand of paint called Color Place spray paint ,one wouldnt think this couldn't be true but the clear is fuel proof after it cures for a week or so. Like all paint keep direct fuel off of course. I would suggest if your that unhappy with the paint job to take some 400-600 wet and dry paper with water and smooth it to a fine finish then spray several lite coats of the clear coat untill you get the gloss required. I have noticed there is a slight color to this clear but its very minute and at a buck a can its a real bargain.
So far I have not found a paint this stuff will react to I have used Krylon for a base automotive paints and so forth. There is one draw back if theres several coats applied it wil dry in a few hours to a point that you can touch it but the flash over sometimes takes a day or two.

And last the engine mount is a easy fix ,measure the thickness of the washers and make a hardwood shim that matches the angle but runs the full length of the mount for complete support to the mount.
Myself I think you have a fine model there and really hope you get many hours of enjoyment out of it. Your the only one that knows the mistakes otherwise from the pics nobody would have guessed it.

What sort of RPM's are you getting from the 120AX with a 16X8 APC Pattern maybe?