Hope this helped you some. Most of the people in our stable oil, cream, water all the time. As long as it is in good condition. If there is too much water it can also cause problems. Use common sense, there is a moisture balance to keep in mind for healthy hooves.
Horses also hydrate their hoves by drinking water.
The enviromental conditions will also be a factor to consider, such as a change in seasons and tempature, mud, dry hard ground,ect. Oils overly applied can be determental and trap the moisture in the bottom of the hoof if applied to the outside horn, and also cause problems if too much is on the bottom. The hoof needs to breath . Rainmaker is oil based , Keratex is recomended to harden soft soles , I am not familiar with Cornucrestine. Hope this helped you some.