Now that these are in the game, it might be worth considering making them a mandatory policy. It seems odd that this is a topic which a government can simply have no opinion on. For initial implementation, start with them all at center, and let the community tell how they think their own country should be represented here.
I might also suggest a slight Gdp boost from favoring smaller business with a longer inertia, as well as better resistance to market shocks like the flash crash. Competition is a major driver of market effectiveness, and there is that expression about eggs and baskets. The incentive to favor larger business would be a quick reaction from foreign investment. If a player makes a major shift to favoring small businesses, the large multinationals would be fast and vindictive, much like how large companies will quickly close any branch that unionizes. On the other hand, the more competitive and ultimately more robust economy from depending on many smaller businesses would take time to establish itself, and voters wouldn’t see the benefit within one election cycle.