Jeff Farris the former importer and or US distributor once said that 200 mm was the limit for a stone on the Supergrind/T2000 which would also apply to your T8. Therefore, according to him you would not be able to use the 200 mm stone you have. Of course you may be able to "just barely" use it. Your best alternative in my opinion is to sell the stone on eBay and buy the correct size. I don't think it would be cost effective to buy a T4 which is what your stone is sized for. Of course the dealer may accept your new stone in trade on the correct one which is your first option and what I would try first.