How to launch second WoW client with different settings or account.
1. Open the folder where WoW client is installed.
2. Find the file "Config.wtf" (should be in subfolder "_retail_\WTF\" or "_classic_\WTF").
3. Copy it as "Config-minion.wtf".
1. Find WoW executable file (should be "_retail_\Wow.exe" or "_classic_\WowClassic.exe").
2. Create a shortcut for it.
3. Open shortcut properties.
4. Find line edit named "Target:".
5. Add a space and then " -config Config-minion.wtf" after executable name.
6. Save properties and launch this shortcut.
From now on, WoW will separate all settings made in this client from your main client. Also, you can use a different e-mail to log in.
Launch clients in the same order.
If you want to switch directly (F1..F12 or 1..9), launch your clients using the method from previous point (via custom shortcut).