Tongera: I'm aiming for Wednesday at the latest. It's a pure narrative post, and those on average take a lot longer to write. I'm debating whether or not to split it into two parts, since what would be Part 1 is done now.
Mathalamus: The Black Death killed a third of the Empire's population, which obviously set back growth a lot. Then there was the Laskarid Civil War of the 1370s, and then the Timurid invasions and the War of the Five Emperors. Without all of those, and with the Ukrainian grain fields supplying foodstuffs, I'd have the Empire at about 21 million, give or take a million (I got that number from the natural increase TTL from 1345-1455, plus the lives lost from the plague). Overall though, because of better sanitation and medicine, the Empire is recovering better from the Black Death than just about everyone else.
As for Macedonian armaments, a lot of that, including everything relating to artillery, was the brainchild of Thomas Laskaris during the War of the Five Emperors. So it got set up in his power base, Europe. With the major port of Thessaloniki nearby, it's also easy to ship the products out to the rest of the Empire. The most secure location in the Empire is either Constantinople (there's no room) or central Anatolia (everything would have to be carried out by land a long ways, which is difficult and expensive).
Evilprodigy: The current Macedonian theme stretches from the Vardar river in the west to just shy of Adrianople in the east. So it's been shifted left from OTL to make room for the Thracian theme.