[Terretta]

Note that out of the box, Airport does two step wireless network extension, super easily.

It supports "extend your network" as hub spoke leaf model, with both wired-to-wireless bases (hubs) and wireless-to-wireless extenders / relays (spokes), and devices (leaves) will connect to strongest spokes or hubs as you roam.

You can have multiple wired-to-wired and wired-to-wireless bases on the same network each with its own wireless-to-wireless extenders or relays. This has worked and been solid (no reboots needed) for years.

Use the full size tower for hubs and airport expresses for spokes.