Please be more specific. What is baseless conjecture ?
If you mean the fact the the first Liturgies were in the evening, then we need look no further than the New Testament.
Matthew 26:20 "And when it was evening... '"
Mark 14:17 "And when it was evening..."
Luke 22:20 "And likewise the cup after supper..."
John 13:2 "and during supper..."
Luke 24:29 "stay with us, for it is toward evening, the day is now far spent... and He took the bread, blessed it and broke it, and gave it to them. And their eyes were opened."
Acts 20:7 "On the first day of the week, when we were gathered together to break bread, Paul talked with them... and he prolonged his speech until midnight...""
I Corinthian 11:17 - 33
Each of these scriptural references to the Eucharist, places it in the evening.
This in *not* baseless conjecture. It is the Bible !
As Cleveland pointed out, the Liturgy was later moved to the morning in order to accommodate those who were fasting before communion. This was *at that time* an innovation. What it tells us, is that an innovation is permissible for the sake of the flock.
You are absolutely right to say that it is the prerogative of our bishops to decide *when*, and *how* the Liturgy is to be performed. What is more, they need no imprimatur from me, or you, to do so.
While it is true that we do not use the Vesperal Liturgy format in our diocese, Bishop Basil does serve the Divine Liturgy in the evening - most notably on his Name's Day, if it does not fall on a weekend. I can tell you this with confidence, as I have attended those Liturgies every year for the past seven years. This too, is not conjecture.
What troubles me about so many of these postings is that while there are multiple references to patrisitcs and liturgical references - there is no reference to the scriptures at all ! Hopefully this is not indicative of what our seminaries are teaching these days ! Tradition and Scripture are inseparable. They are two sides of the same coin. The holy Fathers never made an argument without reference to the Scriptures.
What is far more troubling about these arguments, is the implied criticism of others. "Look at what those Antiochians,.. or those Greeks, ... or those Russians are doing! " Those people, whatever they are doing, are our fellow Orthodox Christians. Last fall, on another web-site, a retired bishop of the OCA roundly criticized the Greek bishops for holding an Aghiasmo followed by a barbeque for the Holy Cross. "What kind of Typicon are following, he said" Never mind, that the offending barbeque was held the weekend *after* the fast day ! It is this kind of self-righteous, Pharisaical bickering that keeps us Orthodox separated from each other. St Paul told us: "Let all that you do, be done in love".
We will not be saved by our perfect performance of the Typicon; but we may be damned by our scorn for our brothers and sisters.
Forgive me for speaking so boldly; but many of my generation sacrificed much for the sake of Orthodox unity - hopefully it was not in vain !
Best wishes to all for the coming Holy Fast