After further analysis, I'm afraid .[<email>].master is 100% NOT decryptable, even under certain circumstances of the server not being rebooted that I was attempting. I failed to realize they had changed the random number generator they used in this "branch" to a secure one, I thought it was only later versions (.[<email>].blocking and .[<email>].encrypted). I have separated these variants out on ID Ransomware for more clarification. The only chance of decryption for free will be if the RSA-1024 private key is leaked/seized (then I would be able to decrypt everyone's files for this variant).
The decrypter will only attempt deriving a keystream if it thinks you were hit by the rare, old RC4 variant, which would have been a long long time ago. If you were hit anytime recently, then you were most definitely hit by the AES-256 variant with the secure key generator, and I cannot decrypt your files. If the decrypter offers to derive keystream anyways, and it corrupts files that it thinks it decrypts, then you were hit by the AES variant, and I once again, cannot decrypt your files. The current decrypter will check if the files you feed it are the exact same filesize, and if the entire file was encrypted past 10MB. Any further PMs about this information will be ignored; I have repeated it over and over, and am getting flooded by messages still.
Lock down your RDP.
In other news, we are still working on a solution for those with the super old .btcware variant (with no email address in the extension). We've had luck with test cases, just not actual victim files yet, so there's still hope.