Download the parts diagram from Kubota or Messicks and get some idea of the shape of the tank, I think the L01s are all in one piece, unlike mine which is split, just to make sure your siphon tube goes all the way to the bottom. Or that all of the tank is uphill from the water separator. Don't think removing fuel filter will work to drain tank on this model.
It is a good idea to be obsessive compulsive on removing water, the high pressure pump on the common rail engines really doesn't like water, and is expensive to replace.