So much more to opsec than using tor. I hope leakers are either ready to be unmasked, or have countermeasures against things like document fingerprinting.
Out of curiosity: How do you counter document fingerprinting?
Probably best if you recreate the document from scratch and "in your own words".
That's dangerous as well, because now your language can be analyzed and compared with other writings from you.
Software like Anonymouth [1] can be used to counter attempts to perform stylometric analysis.