The bucket maintenance should regularly re-seek itself to hashnames in each bucket, and those will intrinsically be returning other hashnames at roughly the same distance, so each bucket will naturally fill itself, it's a very nice self-balancing system that way.

On first boot any hashname should ping all the seeds it has to start.  On later boots it should try to re-ping the seeds as well as any other cached hashnames it elected as high quality and/or that the app was using.