I see what you're trying to do and it looks like it would work. Just a thought, but I have access to a great metal supply down here near me, and I can run out there to see if I can get a scrap piece of round stock next week. If you give me the diameter of your bushing, I can get a piece that is just bigger for you to put in there. I can probably get them to cut it to your desired thickness, as well. I go there for all my materials, so they always help me on the cheap. Once I get them home, I can chock them up in the drill press and bore the holes you need for the bolts and bring them up on a soccer day.
Give me a call, if you'd like, and we can figure out what you need.