I found that running the copies that you don't plan to access minimized tended to releave stress from the system therefore allowing your main one to process better and perform better... lol i'm @ work so can't type for crap...
Long story short:
1) Open EQ II (click your shortcut to EQ II)
2) Accept EULA and then log in, select your character, and turn on auto login
3) All the way logged in? set up trader mode and minimize the window
Skip 4-7 if you are going to only have 2 copies of EQ open.
4) Open EQ II again (click your shortcut to EQ II same as before)
5) Accept EULA and then log in, select your character, and turn on auto login
6) All the way logged in? set up trader mode and minimize the window
7) Repeat 4-6 as necessary

Open EQ II again (click your shortcut to EQ II same as before)
9) Accept EULA and then log in, select your character, and turn on auto login
10 ) Play EQ on last one