TheUnknowable wrote the Sith backstory and is in general control of that Order.  If you go to the OOC, he has the second post which has information for that.

[url]http://www.roleplayerguild.com/topics/87772-star-wars-opposing-forces/ooc[/url]

But to answer your question, the Sith are small like the Jedi, but unlike Palpatine they don't have established lines of power that are helping them with their goals.  Right now, they're working under the guise of an archaeologist and his workers at a dig on Korriban.  Most of the people there are just hired laborers, there are two apprentices(there's a third who is off world doing other errands).

[@ArcaneUnit]  You would need a proper CS, we're freeform about it other than the stats and skills section.  My CS on the first post is a general model(though you should be warned that the stats in that CS are out of date).

As for power tiers, all Apprentices start with the same stat points to allocate, and you can grow in power and skill as the RP goes on.  So there isn't really an upper level, and a n/10 measurement would be meaningless.  

If you want to apply(both of you) send a CS to me through PM.  Be sure to read everything in the first two posts of the OOC.  You can skip the "beta battle," and the "npc" sections, though.