Well, I've never managed to pull off something like 'farming' Hyperion Shrinkers (giving the tech away so AIs will build them and then taking the worlds), but when a given map makes it possible, I sometimes like to focus wars on collecting other civ's Super Projects before I completely break them.
I've had several Econ Capitals in a few games, although it took some time after capturing each additional one to get the planets properly buried in Banks/Stock Exchanges. Even getting just one additional Shrinker can make a big difference in your total fleet strength, at least if you're able to get most of your ships upgraded in a timely fashion.
