A few web pages that I found useful when writing scripts to set up windows with particular positions and sizes in Ubuntu 12.04 LTS:
Automate opening of nautilus windows? - a thread at Ubuntu Forums
wmctrl examples from Spiral of Hope
In the Spiral of Hope page I am not sure what the constructs of the form [#r -r] are meant to do. Maybe they were part of the option syntax for earlty versions of wmctrl? Anyhow, the examples seem to work if you replace each occurrence of [#r -r] by just -r (and similarly for the other [#..] constructs).