Waterproofing from the inside almost never works. It traps moisture within the wall where it may cause serious damage to the foundation, especially if it should freeze. Rock foundations were often designed to allow water through where it was then directed to a cellar drain.

The best things you can do are make sure the grading slopes away from the foundation, gutters (if present) are clear and downspouts send water away. Having a bone dry cellar with a stone foundation is probably not possible. The fact that you saw no standng water is a good sign.