I always put some emphasis on player controlled harvesting, to make it worth, but also challenging. This is why ive introduced these tiberium dropzones, which are mostly at the center of the map, but near a tibfield. So if you want to harvest for your team, your team should dominate the center or an escort force.
Another advantage is, that if silos are detroyed, the team is still able to build a harvester, to gain much money. But its much more challenging to secure the harvester, taht has to harvest at the center of the map, than silos, throwing out money automaticly