Set the inital size of CCK field displaying a single swf file

How can I set the inital size of CCK field displaying a single swf file?
The swf comes with its own viewer, having been converted to a swf from a pdf using pdf2swf. If I display it in the body of a node using the swf filter input format and put something like [swf file="flash/myfilename.swf" width="900" height="1100"] in the body field, it will open in a window 900 by 1100. How can I get the same effect when uploading into a cck field?
I can set the canvas size for flowplayer but I can't use flowplayer for a single swf. Is there somewhere I can set the canvas size of a cck field?

many thanks

Colin