I didn't have much luck with dating with difficult children. I agree that keeping it "light" is best for now. I know it's difficult, because we all get lonely, but I simply found it impossible to maintain a serious relationship while my difficult children were so unstable. I didn't have the time or emotional energy to commit to someone else, and the stress of worrying about their reaction to my difficult child's antics was just not worth it. I dated, but avoided getting serious. The few times I attempted that, it was a disaster.
As for when to disclose anything, I would definitely wait until you've known someone awhile. Perhaps give them bits and pieces of information, slowly. They don't need to know everything up front .. let them get to know YOU first, as an individual, and not just as difficult child's mom. This also protects your difficult child from getting to know someone and then having them disappear.
Dating can be quite the juggling act ... hang in there .