I have only used dewaxed. That you can thin for sure. Not sure about the waxed. People thin the dewaxed all the time. I looked at some woodworking sites that recommend thinning waxed with alcohol. Even Bullseye. They also recommend NOT using anything but alcohol though.
Curious why you chose to use the waxed product instead of the dewaxed. I have never used the waxed so I don't really know what advantages there are to using it?