ThorUI is setup for 1024x768 and up.
once in game type /load_uisettings and you will have a list of options to choose from. One of which is the 1024x768
Also note:
You can click (ALT+O) while in game, this brings up your options.
Click on the "User Interface" button and look for the "Unlock all Windows" option.
Using that unlocks all windows and allows you to move them around to your hearts content.
You can also close and resize all hotbars.
Post in the ThorUI AU forums for any further assistance.
Cheers!