The stones were recommended to be used with oil, thats what FGBC wrote in their Bulletin of Guarantee.

I also prefer to use oil or water glycerine to finish on those stones. Progress to 10k or 12k and proceed with several laps of oil on the stone....

Actually as you read Euclids posts, there is no right or wrong. Feel free to try out both or more procedures and report back here what suited you best.