Historically the first choice is the one that fills first, making server 1 a very risky server to "plan" on choosing if you want everyone to have adequate time to choose to move to server 1 during the time window.

If you remember, Cornelia was the first server to hit max capacity at the start of FFXIV's launch for that reason and gave the server full, choose another, from day one and onward.

Also if you want to be "CORNELIA" there would be no way to tell which of the 10 server's is Cornelia... sure its FF1 and the servers started in that pattern but some of the first 10 servers are not the 10 most populous (Wutai for instance) so you can't assume they'd name them to that schema. Its probably best to just choose a server you know won't fill up quickly so that everyone you want to play with can get in before it population locks.

For instance I could say Server 1 is going to be named Selbina because it has the #1 highest JP population right now (last time I saw a reading). Which would make Cornelia Server 4 if they decided to name from Top->Bottom populations (for that particular reading it was 4th, but may not be the case overall).
You have missed the point, we dont actually care what the server name will be, we are reffering to server 1 as cornelia server because we want to move there as "Cornelia".
We will use the new name of the server when it will be renamed.

Now about your concern of overflowing world 1, up until now there is nothing indicating that this will happen.
Everybody is thinking that world 1 is gonna be overpopulated so everybody choose to go on a different world, making world 1 a safe place to go for us.
Also if we make our intentions of going to world 1 known to other people, then they will choose a different world for them.
It's not that there are this many people playing the game in the first place and most of them have already decided on where to go.

Now all this planning might not even be needed cause Yoshi-P is thinking on changing to Plan 2 so we have to wait untill the week is over.