To answer your original question ----

The waist of the jacket is a little large. To re-cut it though would take a good tailor. Preferably one with experience making military uniforms.

It would entail taking in the side and back seams. Don't touch the front at all.
The placement of the shoulders seems perfect. It just needs a little tweeking in the curved side and back seams.

If you're anywhere near a military base go see one of the tailors in the nearest town. Find one with a lot of mess dress jackets in his shop for work. This shop should be able to do the job very well.