I manually onboarded each user in Budapest (from my group of friends) and learnt a lot in the process. They very quickly highlighted a number of bugs and improvements that I've now moved to fix – the majority of them were technical rather than product-level.
This first 10 in a concentrated area now starts to help build local momentum. With a geographic social app, having a local critical density is especially important – this app just connects people, and without people nearby, it offers nothing... which = unhappy users.