Caulking is a finishing touch that prevents infiltration of bugs and stuff [and floor washwater] to the area under the toilet and around the soil pipe and flange, and prevents sewer gas from exiting around the base, if it should come through a faulty wax seal. It is not a method of securing the toilet to the floor.
NOW, all this said, you realize that the Guinevere uses a Toto Unifit adapter which is mounted first, and then the toilet is lowered onto the already-installed adapter, right? Indeed, that method of installation should make for a really secure fit, because you mount the adapter to the flange, and drill holes and install screws to firmly connect the adapter to the floor. The toilet then slides down onto the securely-mounted adapter, making a very firm connection. Having just installed a Carlyle II which uses this method, I can't for the life of me figure out how you can end up with a toilet that "slides around", unless that adapter isn't connected to the floor at the places where it needs to be, i.e. at the drilled, anchored holes other than where it is mounted to the flange.
You can find a pdf of the installation instructions here: http://www.totousa.com/Portals/0/Pro...IM,%20V.08.pdf I am sure that you read them before, but it seems like maybe you did miss a step? Good luck!!