Sorry Andi, I have been busy at home and also flying my small aircraft, so I didn’t get a chance to reply to your points. You are certainly not a hopeless case, as your questions show a good understanding already.
I am now relaxing in the garden with a beer or three, so it would not be a good time to try to respond!
If I can ask for your patience, I will respond as soon as I can give a sensible answer. Hopefully tomorrow, but no promises!