Great advice, Jaybird. I would add that as far as the end with rivets, just drill them out and put new ones in. If you don't have a rivet gun or know someone with one, they can be bought (complete with pop rivets) pretty cheap.
Do you have an owners manual for the bike? Some of the books are pretty good at walking you through the jetting. You stand little risk of motor damage with a lean pilot jet, but before you lean out anything else, be sure that you are making the right choice. We would rather see you spooge a bit rather than have a meltdown! Many bikes spooge a bit even when jetted properly, especially if you don't run wide open on a regular basis. Different brands of premix oil have different characteristics as well.