It's all straight forward stuff.
The specs from the factory are now so out of date that they realy don't mean much.
Forks are down to riders weight etc but seem to work best with approx 250ml of 10 weight oil. However if they are worn , which most are by now, you will have to experiment.
Rear drive is EP90 if you are in a hot climate or better still 80W90 as a all year round lub. To change it correctly you have to strip the drive unit, ie; remove the output drive plate, as there is no drain plug.
Engine oil is down to riders preference and wallet. Just bear in mind that they ran OK back in there day on normal oils, so super expensive synthetics are not always necessary. I know bikes that have been running perfectly fine for years on cheap 20/50 and also owners who will only have the most expensive race oils. The main thing is to know what has been used before or you might upset the clutch.
The owners manual is bloody useless by the way!
Cheers.
Dorian.