I have been reading more and more about people using oil on waterstones for that little tiny bit extra, especially on Coticules and BBW's

First there is no doubt that it works, so please don't tell me how great it is... what I am asking is how did you test the stone ???

Both of these stones work, with the release of slurry when used with water and a rubbing stone or plate, so how did you test for oil absorbtion on the stone ???

Does the use of oil inhibite the production of slurry??? over the long run have you wrecked/changed your stone
Have you dedicated one stone to an oil finisher much like a pasted strop and it can't go back???

So what tests did you use????