Sorry to come into this late, but one question for you: what are these six official styles of chant? And how does one become "official", as it were?
THe ARabs tend to favor more of a "minor" key feeling, especially with tone 2. ARe both traditions taught or is preference given to the Greek style?
There are easily more than six official styles of chant within the Byzantine tradition (Damascus' being one). All classes at Holy Cross are taught from within the Constantinopolitan tradition of the Great Church of Christ. Students are exposed to other styles in private study, chant groups, etc., especially in recent years wherein students from Balamand have been coming in greater numbers.
I think saying "official" makes it sound like there is a group who decides these things, perhaps a better word to use would is schools.
In my studies I believe we can identify the following different schools in no order...
Some of these schools are more closely related and can be indistinguishable to the ear. What sets the schools apart is the intervals in the scales and to get into that would require several pages and and decent understanding of how byzantine chant works.
I would not identify Ohrid (your Orchid) with Serbia, as it was an important religious center of the Bulgarian Orthodox Church. From the Wiki:
"The recognition of the autocephalous Bulgarian Patriarchate by the Patriarchate of Constantinople in 927 AD makes the Bulgarian Orthodox Church the oldest autocephalous Slavic Orthodox Church in the world, which was added to the Pentarchy of the original Patriarchates. The seat of the Patriarchate was the new Bulgarian capital of Preslav, although the Patriarch is likely to have resided in the town of Drastar (Silistra), an old Christian centre famous for its martyrs and Christian traditions. Around 990, the next patriarch, Philip, moved to Ohrid (in present-day south-western Republic of Macedonia), which also became the permanent seat of the Patriarchate.
After the fall of Bulgaria under Byzantium domination in 1018, Emperor Basil II Bulgaroktonus (the “Bulgar-Slayer”) acknowledged the autocephalous status of the Bulgarian Orthodox Church and by virtue of special charters (royal decrees) set up its boundaries, dioceses, property and other privileges. The church was, however, deprived of its Patriarchal title and reduced to the rank of an archbishopric. Although the first appointed archbishop (John of Debar) was a Bulgarian, his successors, as well as the whole higher clergy, were invariably Greeks. The monks and the ordinary priests remained, however, predominantly Bulgarian, thus allowing the archbishopric to preserve to a large extent its national character, to uphold the Slavonic liturgy and to continue its contribution to the development of the Bulgarian literature. The autocephaly of the Ohrid Archbishopric remained respected during the periods of Byzantine, Bulgarian, Serbian and Ottoman rule and the church continued to exist until its unlawful abolition in 1767."
(Now note well the following facts)
"The struggle between the Bulgarians, led by Neofit Bozveli and Ilarion Makariopolski, and the Greeks intensified throughout the 1860s. As the Greek clerics were ousted from most Bulgarian bishoprics at the end of the decade, the whole of northern Bulgaria, as well as the northern parts of Thrace and Macedonia had, by all intents and purposes, seceded from the Patriarchate. In recognition of that, the Ottoman government restored the once unlawfully destroyed Bulgarian Patriarchate under the name of "Bulgarian Exarchate" by a decree (firman) of the Sultan promulgated on February 28, 1870. The original Exarchate extended over present-day northern Bulgaria (Moesia), Thrace without the Vilayet of Adrianople, as well as over north-eastern Macedonia. After the Christian population of the bishoprics of Skopje and Ohrid voted in 1874 overwhelmingly in favour of joining the Exarchate (Skopje by 91%, Ohrid by 97%), the Bulgarian Exarchate became in control of the whole of Vardar and Pirin Macedonia. The Bulgarian Exarchate was also represented partially in southern Macedonia and the Vilayet of Adrianople by vicars. Thus, the borders of the Exarchate included all Bulgarian districts in the Ottoman Empire."
Of course, after WWI, the Serbian Kingdom also started an assimilation program targeted against the Bulgarians in the modern day Republic of Macedonia. Thus, it is grating to the ears of Bulgarians, so-called "Macedonians" and non-partisan historians to have Ohrid described as anything even close to Serbian.
To bring this tragic tale to the current day, Ohrid currently is the seat of the Archbishop of Ohrid and Macedonia--the Primate of the Macedonian Orthodox Church (which is accepted by neither the Bulgarian or Servian Churches). A little recent history from Wiki:
"In 1959, the Macedonian Orthodox Church was declared as the restoration of the Archbishopric of Ohrid. The declaration was celebrated in a common liturgy by Macedonian priests and the Serbian Patriarch German in 1959 in Skopje. The Archbishop Dositheus II was enthroned as Archbishop of Ohrid and Macedonia, continuing in the lineage of the Archbishops of Ohrid.
In 1962, the Serbian Patriarch German and Russian Patriarch Alexius I visited the Macedonian Orthodox Church on the feast of Saints Methodius and Cyril in Ohrid. The two Patriarchs and the Macedonian Archbishop Dositheus II celebrated Holy Liturgy marking the first occasion where the leader of the Macedonian church met with heads of other Orthodox churches. (Carl: we see here that even the Serbian Churh had renounced the Serbian-ness of Ohrid and Macedonia by this time).
On July 19, 1967, in Ohrid, the Macedonian Orthodox Church self-declared autocephaly from the Serbian Orthodox Church, as was the will of the church's faithful, but as of yet remains unrecognised by other Orthodox churches."
(On the other hand) "The Orthodox Ohrid Archbishopric (Macedonian: Православна Охридска Архиепископија Pravoslavna Ohridska Arhiepiskopija) is an autonomous Eastern Orthodox archdiocese in the Republic of Macedonia under the jurisdiction of the Serbian Orthodox Church. It is the only canonical Orthodox Church in R. Macedonia and is in full communion with all other Orthodox Churches."