Headlands are done first as you would with grass bales and combine harvesters.
Mow > windrow > pick up with forage harvester and have a few trailers carting back and forward to a silage pit. In the UK the more popular use for forage harvesters is similar to bales. In game you'll only be able to use the hired helper with corn or whole crop (regular grains for example). In reality they're used on all sorts of fields, big and small.
