There is no magic to figuring out how much oil is needed for an oil change. If the Norge's oil is at the proper level before the oil change, just add the same amount back in minus a very small amount and that is all it takes.
The method is rather simple. Drain the oil including that from the filter into a 4 liter (or 1 gallon) jug from a previous oil change. Mark the height and transfer that to the new one. Drain the new jog to match the line.
Fill the Norge after the drain and go ride it for the prescribed time. Check the oil and adjust as needed.
No going back and forth checking numerous times. It is a 1,2,3 done thing.
No, the filter will not retain enough oil after emptying it to make enough of a difference that you can't go out and ride it to check properly and adjust. You simply put a small grate over the pan into which you drain the oil and let it sit for a while. What little oil will be retained in the filter is practically nothing.
Then going forward you have a nice job from which to measure the amount needed and there is no guessing or adding/checking/adding/checking to bother with.
The very best thing you can do is to not pay attention to oil threads, seriously, as other than a cross reference for alternative oil filters, all the stuff about this weight and that weight doesn't help you. Use the weight prescribed, the type prescribed and be done with it.