I'll give it until 6pm EST today for voting, but I have a proposition as well.
I could start a YouTube channel and play the nation you all choose, on a annual or biannual basis as intervals/turns, and post that video on turn results, and pause for big random events. While it'd be easier to get a visual of what's actually going on, it'd lose immersion. I'll leave that as an option.
As for the two nations that are likely to be picked:
Venice: Starts as a Serene Republic with a fairly strong navy and decent army. The Republic mechanic obviously brings elections, which reduces the likeliness that y'all get stuck with a shitty leader. The bulk of your land is in Northeastern Italy of course, with provinces on the Adriatic, the island of Crete and Naxos (an island on the Greek coast) as a Vassal. Venice itself is one of the most lucrative trade nodes in the world, with Genoa and the English Channel being the other two.
The Ottomans are going to be your biggest threat at the start, and it'd be much easier to build a strong alliance against them as opposed to Byzantium, given bigger nations are more likely to ally you if you're a decent size yourself. Austria, Poland, Hungary and even Mamluk Egypt sometimes are options to mutually beat down the Turks.
Byzantium: Has seen better days. Kicked out of Anatolia, all you still hold is Athens as a Vassal and southern Greece. Small army, decent-ish navy, small economy, and it's going to be harder to get bigger allies. Serbia, Bosnia, Wallachia and Albania are viable choices.
If Byzantium is chosen, I'll give a bonus to compensate.
It just depends on what flavor you're going for. Venice would be a better choice if you want to get off to a faster start, Byzantium would be better if you want to stay rigid true to the nature of the quest.