Thanks J! There's no time limit on the project - it will probably take years. There are over 6 million African Americans enumerated in the 1880 census and at the beginning of 2024, we had ~260,000 African American profiles on WikiTree. But we'd love it if a lot of people join in this month during Black History Month and we'd welcome anyone who wants to continue working on it after that until it's complete.
We're not making connection to the big tree a main focus of this project, just family groups connected to each other. But we're hoping that as people work through specific towns and counties, connection will happen naturally, at least in locations where there was a significant African American population. This was the case when our Ohio team piloted the project in a single town - I'd guess that by the time we had about 30% of the profiles for that town created, we were finding that most new profiles we were creating could be connected right away or by adding just one or two extra profiles. At that point, we usually had at least one member of the 1880 census household who was either married to someone who already had a profile or who was a child or parent of someone who already had a profile. Of course, results will vary from location to location, depending on things like how much intermarriage there was within the community and whether the population tended to stay put or whether it had a lot of migration.
But also, if you like to work on connecting, you're welcome to add additional generations and collateral lines until you get families connected - you're not limited to one household at a time from the spreadsheet.