I bring 3-5 mk2 engineers and v+rightclick them a far distance from hostiles so they can just teleport in and heal then teleport out of danger.
The only problem with this is that in intense combat ships don't heal for 3 seconds after they have been shot. Using tugs takes them out of combat so they are no longer recieving fire. It strings out your forces, but it preserves them. My experience is that it reduces my losses by 20-75%, depending on amount of ships/ amount of enemy ships. It also let's you alt attack because the repaired ships form a defensive barrier around your entry wormhole, protecting knowledge raiders without having to dedicate units to it.
My MRS forms, for large assualts, the anchor point for everything, and adds what feels like a continuous stream of reinforcements. Engineers behave similarly, but only heal one unit at a time, dont' remove units from tractor, and don't pull units away to a place where it is actually possible to heal them. But you can always do both, MRS is not that expensive in either knowledge or build costs.
It's also awesome in combo with leech/parasites starships because it pulls out all your new units and gets them up to full health.
Badass....
