(My first post here )
The point of lubricating a whetstone is twofold - to carry away the metal particles taken off the blade, and to ensure to process does not generate too much heat from friction, which could de-temper the edge.
Honing oil is the best, but any light oil (even sunflower oil) will do, if you want an oil-based stone, OR water, but never mix after the first use.
I like Arkansas stones for fine finishing, and use water for the best cut.