I've done probabally 20 of them, and they still take me 6 or 7 hours. You can get it apart pretty quick, but carefull reassembly is a time consuming job. I doubt very much the mist you saw was oil or anything from the evap. If it could spew anything, it would empty the system is seconds, litterally.
Also, if it leaked that bad, you would be able to verify this by removing the blower motor housing. (behind the spare tire carrier and above the battery)
Such a large leak would leave the evap coils very wet looking. If it did not leak that quickly, I would add dye if you can before pulling the blower motor so you can check it, and the expansion valve for leaks, while you are there.
MB