In order to change your server seed (not world size), first login to the control panel at http://cp.chicagoservers.co
Then, go to Commandline Manager > Custom Commandlines > New
Type in a Description for your custom command line such as "Custom".
Check the box next to "Server Seed" and enter in whatever number you want. It must be between 5-10 digits long.
** CHECK THE BOXES FOR EACH BOX YOU ENTER SOMETHING IN TO OR IT WILL NOT APPLY IT.
A screen identical to what is shown above will appear. The check boxes determine what arguments will be added to your commandline.
* At a minimum, you will want Description, RCON Password, Gamemode, Identity (save directory name), Map, Worldsize, and Seed filled out. (Custom world URLs for advanced users should uncheck world size and world seed).
Once done, click save. You will be brought back to your custom command lines.
Select your custom command line and your server should automatically restart. If it doesn't, restart your server. You can always come back to your custom command line and edit whenever by clicking Edit.
** Changing your server name can be done in the configuration file. For more information on that, read this article: https://chicagoservers.co/clients/index.php?rp=/knowledgebase/17/How-can-I-change-my-server-name.html