I have 4 monitors, but I am limited two 2 X screens due to my 2 nvidia cards. My current screen setup is:

+------------+------------+
| X screen 0 | X screen 1 |
| monitor 1  | monitor 3  |
+------------+------------+
| X screen 0 | X screen 1 |
| monitor 2  | monitor 4  |
+------------+------------+

That is, the nvidia driver combines monitor 1 and monitor 2 into the 1st X screen and monitor 3 and monitor 4 into a 2nd X screen.

To recreate the effect of 4 separate X screens, I use XMonad.Layout.LayoutScreens to create a 2x2 screen setup. The command I have in xmonad.hs is 

    layoutScreens 4 Grid

This works well. However, I would like to rearrange my screen setup to be instead as follows:

             +------------+
             |            |
             |            |
+------------+------------+------------+
|            |            |            |
|            |            |            |
+------------+------------+------------+

Using the nvidia configuration tool, I can create the above as:

             +------------+
             | X screen 0 |
             |            |
+------------+------------+------------+
| X screen 1 | X screen 0 | X screen 1 |
|            |            |            |
+------------+------------+------------+

or
             +------------+
             | X screen 0 |
             |            |
+------------+------------+------------+
| X screen 1 | X screen 1 | X screen 0 |
|            |            |            |
+------------+------------+------------+

However, once I do that, how do I use XMonad.Layout.LayoutScreens to create a 4 screen setup again, now that the positions of the monitors are different (and I can't use Grid to split up the layout)?

TIA