it has been a while since I last took my MS out for a spin. When I changed the ratio I just used the normal belts and adjusted the tension via the diff holders.
Although I am sure I posted about it on my blog when I did it. http://www.thercracer.com
I will take a look tonight / tomorrow evening
TRF419, TBEvo6, TT02, VDF, TRF501x, TRF201, TRF101, Mi5, X-Ray T4-13, BD7 2014, A700 Evo, WR-02G