Ok thnx guys Im actually workin on this and may end up making it either a standalone page that sets the style id or an extra $request on one of the pages probs index
Basically im using the Js to detect Resolution and then setting the styleid dependant on this so as users on resolutions dont have to hit the usercp and set there style, all they need to do is hit a quick link to "optimize" style and once done they will run the corrwct style for there resolution
As at artorg we have 2 versions of the site, default 1024x768 and below then all thew users above this style who use a modified master style called Artorg - HIGH RES