All the plugs you need to use to drain your fluids will take a 5/8s socket.
Don't mess with any of the other ones.
Primary is below your primary cover on the left side of the bike.
Motor oil or crankcase is facing the front of the bike on the left side.
Tranny is back and veritcal on the right side.
Get new o-rings for any plug you take out, then determine if you need to use the new by inspecting the old o-ring.