Mix Engineer enquiry

I am working on my latest album project for Soulnaturals, it's a Soul, Funk & Disco album fusing gospel, orchestral & opera elements and will feature various guest lead singers from around the world. The first track is ready to mix, I'm going to release it as a single as the album is being made. I would send you mix ready WAV files, 35 tracks, could you tell me how much for mixing 1 track, how long the turnaround & how many revisions, and if it includes mastering please. Also it would be good to know if you record audio at your studio, eg. vocals, I live in London around W6 so it could be a good option for me if so. Cheers for now, Tony