Today, I got a lot of work done on my drum, and in the process, my project has strayed very far from what I originally intended; however, I am satisfied with what I am going to call the final version of my drum.
The first thing I did today was dremeling and clipping the metal handles off the buckets. This is so they lie flat on the ground and are less likely to snag on something. Afterwards, I filed the freshly-cut edges down so they would not be sharp. I then attached the handle to the bucket. The screws that came with the handle were wood screws, so we replaced them with a thinner threaded screw and a nut. The screw from the handle interfered with my original plan of a sliding bucket, but as my plans shifted, a hidden benefit of the screw was revealed. It prevented the two buckets from fully fitting together, creating a gap that sound could escape through. The gap gave the instrument more of a "live" sounding, resonating chamber. The last step I took was to drill holes on the top of the handle bucket and drop in the rivets. This took the most time, as I was experimenting with different rivets and placement. I decided the lighter rivets should go on the outside (so they do not pop out), and the heavier rivets on the inside, to maximize rattle.
This is probably the last stage of my drum. Even though it changed over the course of the project (from a pitch changing drum to more of a snare), I am happy with it.