Android tablet 10.1 and guiTexture gui placement with unity

I have a problem with guiTextures on a 10.1 android tablet and how they are placed.

1. I cannot get guiTextures to layer and to be placed correctly on this screen resolution. I set the pixel inset and positions to 0,0 (my texture is exactly the screen size so it should line up to 0,0). Why doesnt it line up when i build my app?

2. the screen resolution of my tablet is 1200x800. This resolution is not selectable in unity's editor. Can i create a custom resolution for this tablet so i can select this?

3. How do i order guiTextures? And same for using the UItoolkit, as changing the z-value doesn't seem to change ordering.

Is there an easy script or variable to use for position gui elements? Shouldn't position values in the guiTexture's transform be screen pixels? Why are they values between 0 (left side) and 1 (right side) of the screen?