The kits I've seen installed were serviced with 5w Bel-Ray fork oil, which has the following viscosity:
Viscosity 15.8 - 18.5 cSt @ 40 °C (104 °F)
This roughly corresponds to Ohlins 01311-01 fork oil.
http://oehlins.info/downloads/highpe...sionfluids.pdf
Ohlins R/T forks are valved for a heavier oil
AFAIK... something closer to a 7.5w oil.
If you're installing a (newer SBK valved) 25mm kit, it's probably valved for a 5w type oil, but not all 5w fork oils have the same viscosity index, which is why its important to verify the cst value of the oil you are using.
Take this post with a grain of salt. I'm not an expert on the subject. The ideal would be to contact Ohlins directly and then cross-reference the Ohlins oil type cst value to the oil type/brand you prefer. The benefit of doing this is that you should be able to get equivelent performance while using fork oil which is less than 1/2 the cost of the Ohlins-branded oil.