if you want WoW windowed just open them and go the video settings and click windowed mode.. the size of the windows is completely up to you tho.. i like to keep the main window larger with the alt windows poking out a little on the side... this is just so i can see that there is movement in that alt window to make sure its following, but thats just me, feel free to experiment and figure out what works best for you.

p.s. usually if no one answers your question its because its probably in a sticky or already been asked. try using the search, im sorry if you already know this:P

well GL!