You are most welcome.
Nope. The latex rubber is to be placed underneath the stone to prevent it from slipping and abrading against the counter-top.
Anyway, to stabilize the blade during sharpening, I suggest using this neat gadget:
Minosharp Sharpening Guide Rails Set (2 pieces) [photo: Sointu USA]
The guide rails are sold as a set which includes a small and large guide rail. The small guide rail is suitable for knives with blade lengths less than 150mm (6 inches). The large guide rail is suitable for knives larger than 150mm. The guide rails are lined with plastic to minimize scratching on the knives during their use. Any time you remove one of the guide rails from your knife, rinse and clean it thoroughly to remove any residue from the stone that may remain inside the guide rail. To further insure that no residue remains, it is recommended that you pull a clean towel through the guide rail after rinsing. If you fail to remove all the residue from the guide rail, the residue may scratch the knife the next time the guide rail is used.
[ATTENTION: Do not use guide rails when sharpening traditional Japanese knives.]
You can purchase them from Tangs Orchard.