Dang, how frustrating! Are you working on an older bike? They can be so tedious locating proper parts...
As far as the paint, you should probably let it set way longer than the directions say. I painted my '56 schwinn cruiser last winter and let it set for 2 days and then put the seat on, the paint was still gummy and got totally messed up. I let the bike sit another 5 days before I put anything else on. The paint was much harder and more stable by that time. I probably could have given it even a few more days after that. Also make sure you have it indoors if you live where it's humid.