Don is the vB Product lead -
http://www.vbulletin.com/forum/membe...4-Don-Kuramura He's written a bunch of articles on the CMS and on styling.
As for your method of doing it, I have no idea if it's a good idea or not. I find it easier to use the default way of doing it, but I suppose if you want to do it your way, then you may. You'll probably have to edit the header template though. And then add your css either at the bottom of the vbulletin.css file or using some other method to add css.