Hi,
I deal with audio edits very often for my clients and myself.
15 GBs is a big size, but it could be done. You wrote that the recordings were re-mastered. So, you are not satisfied with the results? Why do you want to re-do it?
If you want me to do the editing, then I would need an original file(s), unprocessed.
And then I can see if I could edit, polish, master it well.
Best regards,
Andrei Autumn