I mix them into my other groups as defense. Yet again, organisation depends on your strategy. Once you have a dozen, ideally more harvester ants, you can start getting some Majoris. Try focusing on the area north of your starting point, try to both harvest for yourself and deny the enemy easy access to leaves.
And then 2 groups of mixed ants that clear out areas of enemies to get at more leaves. I keep 1 group that just consists of small workers which I use to 'clean' up almost empty areas. How you organize now depends on the strategy you want to employ. Once you have around 20 small workers (Your mileage may vary) start working on proper worker ants. Split them into 2 or even 3 groups, micro manage to ensure that they do not run into predators repeatedly, and pick the immediate area around the nest clean. Get a bunch of small workers in the beginning.
