So my WoW priest went over to the dark side, and thanks to the help of my readers switched to a good raid shadow build. I know about the importance of hit rating for shadow priests, but as that sort of gear is also needed for a lot of other classes, I never got any pieces for an off-spec set. But being a jewelcrafter I had a lot of gems in stock, and just switched all my gems for +16 hit rating ones. That got my hit rating up to 190, and my miss rating down to just under 2%.
So now I needed a way to test the build and the suggested spell rotation in a raid. Luckily somebody I know was just organizing a raid to Vault of Archavon heroic, and I was able to join. And for a first try that didn't go too badly: Nearly 2.5k dps. After that we did another VoA raid in 10-man mode, and I was second place among the damage dealers on Recount. Not half bad for wearing the wrong gear and being new to shadow priesting.
I hope I can get into a Naxxramas raid with my guild this week for another shadow test run. But I think I'll switch back to holy right afterwards, healing is more challenging, because you need to react. But when dual spec comes with patch 3.1, I'm a lot better prepared now. Thanks again to all who helped with advice!