Once you start pushing boards together to allow millions (or at least more than 2) to play, some small changes need to be made in order to better manage the larger play space.

No Home Row

You are no longer a big fish in a small pond, so you do not receive the luxury of "friendly" board squares. When the game begins, a player simply makes their initial claim at least 7 squares away from any previous claims. From that point on, all growth is based off existing territories, and you're completely finished if other players take over all your territories.

Scale

With the larger board, you are now able to take advantage of the ability to scale once you subsume an 8u. In choosing to do so, you effectively quarter the board complexity for you. Plan ahead, because any stray 1u tokens become inaccessible (not removed from the board, but beneath your threshold to notice; essentially microscopic), and all your other units drop a size, too, but are now operating at double the scale. That means your previously immobile 2u territories are now represented by larger 1u tokens that can be manipulated as you might expect.

You are also much more dangerous to other players because they need to be coordinated to win a conflict. If, for example, you have a 1u @ 2x isolationist, another player would need to be have 4 1u @ 1x advocates stacked in order to counter it. Anything else and you're able to run roughshod over their territories, taking over tokens as you go (though they will still be microscopic unless a proper conflict is won).

Broken Scale

As with a broken claim, it is possible for you to lose claim to all your 4u (or larger) tokens at a higher scale. Should that happen, not only does the territory collapse but your scale is also reduced to reflect your new control level.