Openbox: Resize Window According To Resolution

Question

Is it possible to use to resize windows according to the resolution of your screen in OpenBox3? What I want to do is make windows half the screen width with a shortcut. I can do this like this in rc.xml:
<keybind key="S-Right">
<action name="UnmaximizeFull"/>
<action name="MaximizeVert"/>
<action name ="MoveResizeTo">
<x> 720 </x>
<y> 0 </y>
<width> 720 </width>
</action>
</keybind>
But I would like to make it more flexible and to set it to this without knowing how much half of my (1440x900) screen is (720).  Unfortunately resizing after setting MaximizeVert doesn't work which would be a step in the right direction.
Is there a way to resize a maximised window? Is there another way of doing this?

Answer 1

Seems there is no way to do this yet although it should be possible since openbox knows what size to "maximise" your windows to.
Another question: is it possible to perform an action after pressing PART of a keychain? I.E. keybind an action to C-r say and then followed by another key to complete a keychain to perform a different action:
<keybind key"C-r">
<action name="action 1"/> <!-- action when C-r is pressed -->
<keybind key="e">
<action name ="action 2"/> <!-- action when C-r then "e" is pressed -->
</keybind>
</keybind>