Hi, I can only reply briefly right now.
The KG pipe is used only as an auxiliary pipe so that not too much soil slips and falls down in the hole to the groundwater. You have to decide on site depending on the conditions whether you need it or not. Ideally, it goes 4 meters down from the water. The pipe setup is a matter of belief; I would leave it open at the bottom. From bottom to top in the water -> 1m pipe, 2m filter section with 0.3mm slots, 1m pipe. Plunging without help like a winch, pulley, etc., you will hardly manage; it will all be very hard, don’t wear yourself out with it. Make sure you have enough weights. There can easily be half a ton resting on it. Better to mount a protective steel ring at the lower pipe, otherwise, the pipe can break at that point.