I haven't personally done large quantities of tea myself but a man I know has a whole setup where he makes hundreds of gallons and broadcasts compost tea for turf enrichment as well as new beds. I personally have always just taken the ingredients and put them in a sock or pantyhose and tie it to a stick and let it soak in a five gallon bucket for a few days. Then apply it as needed. It's always worked great.
As for your loopers and cabbage worms, I've had the same issue for years, those damn white moths sure are tricky to catch. I've tried diatomaceous earth (works well) and looking under the leaves for the egg sacks and squishing them. One year I had excellent success with companion planting my onions in between my cruciferous veggies so I ha e continued to do that. I had read that the moths hate onions and don't lay their eggs near them. If you do a fall garden, the moths I believe only hatch twice a year and many times you will get few to none with a later crop.
I love the idea of a polycarbonate greenhouse/screenhouse. I would figure that would do the trick! Even row covers help enormously since the moths can't land on your plants.
God they are terrible! Haha
Good luck! If your cauliflower gets infested, soaking the head in a mild saltwater solution helps get them to come out. Admittedly, I'm sure I've eaten a few over the years I'm sure since I've seen a few on the plate haha.
