I wonder if you could get some interesting data about macro effects by giving BI to a whole neighborhood within Oakland, preferably one that historically has had low levels of migration and shops locally. Instead of sampling randomly from the population of Oakland, universally give everyone within a neighborhood basic income (or run a parallel study doing so).
That'd answer some of the biggest questions I have about BI. What happens to rents & housing prices when everyone has an extra $X to spend? What happens to prices in neighborhood shops? To what degree are people willing to travel to avoid high prices? What happens to the social fabric when everyone is richer? Do people engage more with their community when they don't have to worry about basic financial survival? Or do they isolate themselves and enjoy their new toys? If people choose not to work, what else do they spend their time doing, and how does that effect the community?
At the very least, you'd get some really great data about elasticity of rents, housing prices, and local goods which I bet economists would love to have.