For the southern triangle, the Black Sea is of critical importance. Both Russia and Turkey have one fleet in spring 1901, and both could be trampling to move to the BLA early. My personal opinion is that neither of these two countries can afford to have the other on the Black Sea, and hence the only logical outcome would be a bounce in Spring 1901.
The Russian side
Russia normally wants to have a new supply center in Rumania in the fall of 1901. Luckily, Sevastopol directly borders Rumania, so there is no need to move your fleet to Rumania in the spring. A typical deal would be that you take Rumania with your fleet, and only build a new fleet in Sevastopol in case the Turks move to the BLA in the fall.
F (Sev) – BLA
A (Mos) – Ukr
F (Sev) – Rum
A (Ukr) s F (Sev) – Rum
However, this version does not tell the whole story. It assumes that the Russian player can use either Moscow or Warsaw to occupy Ukraine, and that the Austrian ‘behaves’, which means Galicia is empty after the spring.
The Turks can absolutely not allow the Russian fleet on the Black Sea in Spring 1901. Two of your home supply centers would be under direct threat. Hence, as a Turkish player I would always move my fleet to the Black Sea.
F (Ank) – BLA
A (Con) – Bul
A (Smy) – Arm
F (Ank) – BLA
A (Con) holds
A (Arm) – Sev
In case you are planning an attack an Russia, you could move the Army in Smyrna to Armenia. In case you want to play more neutral, just move your army from Smyrna to Constantinople. The real question for Turkey comes in the fall. The Russians will probably need their fleet to conquer Rumania, giving you a great opportunity to conquer the Black Sea. I would recommend you to do this, as it gives you great opportunities in 1902. However, if you are looking for an alliance with Russia, you probably want to move your fleet to Constantinople and to AEG in Spring 1902.
In the case you want to make a move against Russia, an army in Armenia could help you. The army in Armenia could threaten Sevastopol, meaning the Russians would have to ensure that it stays occupied. And what is the main problem with an occupied home supply center: you cannot build there; hence this is a method to ensure the Russians do not build a second fleet in the south.
The downside is that a move from Smyrna to Armenia in Spring 1901 is a pretty obvious attack on Russia, hence you make your intentions clear from the start. The other issue is that once the army is in Armenia it is a 50/50 guess whether the Russians will defend Sevastopol, if they do, and you move there as well, Sevastopol will stay empty, and you have just handed the Russians the opportunity to build a second fleet. So the move is risky, but the pay-off could be great.
My main message is that you will always have to have full attention on the situation around the Black Sea if you play either Turkey or Russia. And never forget the huge advantage somebody gains once he enters the Black Sea.