In Keyclone's maximizer, you should see your entire screen.
You have regions created, one per instance of wow you wish to run.
Each region should physically occupy as much of the screen as you have its dimensions set for.
Under this, you have a resolution setting, which is what wow is set to.
WoW basically thinks each region is your full screen and renders within that window at the resolution you have chosen.

Assuming the resolution is set how you want and the regions are set up the size you want...
All I can think of is ensuring wow is set to run in windowed mode.