CRG Brake variations discussion

Hi guys,
i have the same issue, i have CRG ROK GP (single speed) now i have on the rear green pads so it will be ceramic (duralcan) brake disc. Any chance to buy a new one in Europe?! Is there any notice about how thick brake disc should be before replacing him?
I am thinking that ceramic disc + pads will work better in dry conditions, but is more expensive then steel brake option.
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