controlling multiple screens from the command-line

I'm working on a pdf presentation application, actually adapting
pympress <https://github.com/Cimbali/pympress.git>. It has a "content"
window for the audience and a "presenter" window. The normal use case
will be to have the presenter window   on my screen and the content
window on the projector. Doing this without sighted assistance sounds
tricky. It's a python application using Gtk so I'm wondering whether I
can extract the relevant information on monitor sizes and the like,
perhaps from the Gdk package? More generally, have people found a general
solution for the equivalent action of dragging windows into the right
place so they show on the correct monitor?
thanks in advance
Peter


-- 
Peter Rayner
Clean Air and Urban Landscapes NESP hub <http://www.nespurban.edu.au>
room 371 <http://maps.unimelb.edu.au/parkville/building/200>
School of Earth Sciences, University of Melbourne, 3010, Vic, Australia
tel: work: +61 (0)3 8344 9708; fax: +61 (0)3 8344 7761 
mobile +61 402 752 379, skype: petermorag 
mail-to: [email protected] TWITTER: @raynerstrings