Before you go around balancing the colonies you have to consider their virtues and technological capabilties. Plymouth has no Meteor Defense because they believe nature should be allowed to take its course (thus their opposition to terraformation of New Terra). Eden, on the other hand, believes technology should be used to transform nature to comply with the will of humanity, which is why they tried to terraform New Terra and developed the Meteor Defense. If anyone had a tractor beam, it would be Eden due to its technological superiority over Plymouth and they don't mind manipulating natural forces for their own purposes. Which is also why Eden has a lightning gun, while Plymouth relies on explosives and foam grenades.