i don't know.. that didn't work out, i added a script in the user stylesheet to resize windows to a specific width/height but instead, it threw the page design a little off centre and didn't change the window size.. like it affected the content and not the actual window.. for example in google's page, the search buffer and buttons all got shifted towards the left, it was an interesting layout actually.
obviously it's a gecko thing, i found this link discussing it and it doesn't seem possible to really alter the size of newly opened windows.. unless ofcourse it's a defined site or url like in the case of 'about k-meleon'
http://support.mozilla.com/tiki-view_forum_thread.php?forumId=1&comments_parentId=1537
a work around was by using virtual dimension:
http://virt-dimension.sourceforge.net/ assigning kmeleon's windows to resize with vd works but ofcourse will affect pages with predefined sizes.. obviously not a great solution so skipped that.
anyways.. i rarely if ever select open in a new window so it's no biggie