The current BMW recommended oil I use is Castrol 0-40 European from Walmart. Here's a link :
https://www.walmart.com/ip/Castrol-E...-5-QT/35931146.
I add no more than 6 quarts after an oil change. 6 will put me at the maximum oil level on the guage (not the mid-point). About 5.5 quarts will get me to the mid-point. I would not put in less than 5 quarts or more than 6 without checking your level (even though that means driving the car).
The filter housing cap is plastic. You may be able to turn it by hand but a better way is to use a special cap wrench. Mine has a nut on top the same size as the drain plug. So I don't have to change what is on the ratchet.
I have tried getting the car level but I don't think it makes a significant difference in terms of how much oil comes out. My current method is to use ramps I made from 2x8s to get the front end up 4.5 inches which is enough I can get under there to change it (barely). I have also used little 1.5 inch tall quasi-ramps to raise it enough to get my jack under it and then jacked it. But jacking our cars isn't super simple with the plastic boxes on the side that will not directly take a jack.