I have perfect Russian, ready to cooperate.
1) As a creator: start 5 text (x 500 words) a day and make increase gradually
(limits are around 20-25 good texts a day, this depends on a text complexity and volume)
2) As a proof-reading: as many as you wish, with limits about 30-50 texts a day. I can proof-read Polish, Russian, Lithuanian region languages.