Seedlings went into Flexipots (fabric pots from Autopot) and hooked up to the Autopot watering system with a 47l external reservoir.
I also used airdomes at the base of the pot, covered with leca and topped with the growing mix. Airdomes connected to an aquarium pump.
Topped the growing mix with some diatomaceous earth, mixed down into the top inch. This is the best way I’ve found to control fungus gnats.