I think MACE was kind enough to show you a sample back. The Main thing is to have AFA Buddy cards on the top, and your user name info. It is handy to address but I think most of the time I just Username, Real Name and location. Then if there is room I add date and what I added to the card.
In the Buddy card group it is all private trade type agreements no cards are sent till both people agree, so the international issue is up to each person. But mostly it has not been a problem.
I am not going to be keeping a homers/ address list for this group. But I will add to communicate with your trade buddy if you want to use religious, Political, sexual or gory stuff to be sure they don't mind.