cck flashvideo_video_args and overriding the default video size for widescreen option

I used cck to create text field called flashvideo_video_args and made a some radio buttons to allow the user to switch between:

-i @input -f flv -b 360 -r 15 -s 320x240 -acodec mp3 -ar 44100 -ab 64k -ac 2 @output
and
-i @input -f flv -b 360 -r 15 -s 320x180 -acodec mp3 -ar 44100 -ab 64k -ac 2 @output

my thinking was it would allow them to choose the second option for widescreen video to save there work getting vertically stretched to fit 320x240, but from what can tell this doesn't do anything as the default video size is still set to 320x240 and this what is returned by print flashvideo_get_video($node,array('fids'=>0)); in my video template.

Is there a way I override the default video size, via cck?