Random numbers incoming
Last thing I could find about size of the worlds.
an 8 km world would be 1000 beacons across. (Assuming 8x8x8 beacons)
If they just launch with 10 of these we are going to have 10.000.000 beacons of space not counting up and down, asumming that only 1% of this is used we will have 100.000 beacons of space not counting up and down (And any larger builds will probably use at least double layer beacons. assuming the player can get 100 beacons within short time (Which they won’t) people will have roughly a 128x128x24 area which is pretty large and it will take 3000 players using up this 1% of space if they build 3 high that is. I would say there is space for aproximately 1500 players if they all get 100 beacons quickly and use around 1% of the space in the game.
If the game is filled up quickly though the devs have reasonable time to add new spawn worlds and expand the universe with more small worlds which will use the space more effeciently and more large worlds that will provide exploration area.
But again people will probably not gain 100 beacon each during the first week. So we could probably have double that space, or maybe even more. And remember that people will by the mechanincs be incouraged to lump together, in guilds.