Look at the exploded parts diagram for the proper assembly places, a picture is worth a thousand words.

When you put the washer on stick it on with some grease, when you put the cover back on the magnets will suck it back together and can pull that washer where it don't belong and destroy the stator windings.(guess how I know!) Grease will keep the washer on it's shaft like a little glue, then melts into the hot oil.

Practice putting the cover on a couple times so you know what to expect before you use a new gasket and, or sealer. It will suprise you the first time.

Clean everything good with brake cleaner or acetone and use a high temp sealer on ONE side of the gasket and all around the rubber plug. Let it cure overnight before snugging the bolts again and re-fllling the oil.

You don't want to strip those small bolts, use nothing bigger then a 1/4'' drive rachet with your hand over the pivot NOT down on the end of the handle.

You were wise to ask for advice on this one, it is a little tricky to put back together the first time, and if that washer gets sucked down into the stator windings, it gets expensive.

As the bike ages and goes through more time with a hot engine, the rubber seal around the wiring seems to shrink.

I don't use any sealer on a new gasket - but I do put some RTV sealer on the rubber seal that the wiring passes through.....it only takes a very small amount spread around the outside of the seal.  (I also put a little bit on the wiring to make sure the oil doesn't get past the wires).

The neutral light wire on the other side of the engine gets the same treatment.