Erik, Nice sword.
Try placing a 3/4" piece of ebony at the guard. If you like the look, shorten the maple handle accordingly, and add the ebony spacer.
I think the piece is a little too long to make it without any guard, but the guard can be nothing more than a 1/4" lip ( basically a hand stop).
The style would be called shoto-wakizashi, BTW.
For copper to inlay, go to The Home Depot (or any similar store) and get a foot of bare copper wire in whatever gauges you like. It is over on the cut-to-length rolls. Heat it to a dull red, let cool to loose the red color, and quench in water. That will anneal it soft.
For the decoration :
Make two holes spaced about 1/4" apart, one a little larger than the other, near the guard rim above the spine (12 o'clock on the guard). The larger hole should be a tad closed to the rim than the smaller one. These are the udenuki-ana (cord holes) and represent the sun and moon.
Place four smaller holes, close together, at the four o'clock position. These are the sukasahsi ( decorative holes) and represent a "choji" or clove blossom. Slightly chamfer the holes and hammer in the copper. The simple addition of a little inlay can make a tsuba really stand out.
Stacy