Yes, custom fact is the way to go if you are using Family Tree Builder and you want to visibly track a particular fact. They show on the profile online and you if you export a list of people from your Family Tree Builder to Excel, they will appear and then you can manipulate it, by sorting, filtering, etc. I use it to track my direct and indirect maternal and paternal lines at a glance. Family Tree Builder has a great feature that if you hover over a certain name it tells you what relationship it is to the main person in the tree and in the online version, you have to go into the profile to see the relationship. But I started my numering system before i discovered My Heritage and once I went past 4 or 5 generations and because I'm tracking indirect as well as direct and a lot of my people have similar names, I needed a quick system to tell me who was who and this works for me. I'm glad my idea works for you too