Well I am not Roman Catholic
But I am pleased that you seem to have come to a good place regarding the Roman Church.
As for the Orthodox church...they have an entirely different callendar, complete with different feasts to boot. Their music is very interesting.
Gosbodipomilodge Or thats how it sounds phonetically, is the Russian/Greek Orthdox ulternative to the Kyrie. They are heavily into unacoumpanied chants...if you think this sounds a bit like the literny of the Saints from the Roman Church...I believe that its kinda a cross between the two.
The Video is dedicated to one of the Patriarchs...maybe the one who was in Yugoslavia...I know when he died there was much wailing.