WHAT ARE THE GREGORIAN MASSES?

QUESTION / COMMENT?

I was wondering if at some point in the near future you guys could talk again about the Gregorian masses during your radio show? I recall in the past you talked about it but I no longer remember many of the details.
If I remember correctly, I think you guys said that offering 30 of these masses consecutively for the soul of a loved one would allow them to leave purgatory faster.

My questions related to this are:
- What are Gregorian masses and how do they differ from the ordinary masses that we might go to on Sundays or on weekdays?
- Can any priest at any church say/preside over a Gregorian mass or do priests have to have special training in order to be able to do this?
- Can only some churches do this?
- Does it have to be 30 consecutive masses, or can they be spaced out so long as they are done within a certain period of time?
- And what is the basis of Gregorian masses (as in, are they referenced in the Bible or other Church documents/traditions)?