With the retirement of our senior programmer a year ago, I am now our Dreamweaver "expert"!
Then you are in deep trouble, especially given your template design. Neither of the elements you mention (nested templates or template parameters) actually make your life easier (in fact they make it much more difficult). In the event that you'd like to hire someone to do the work for you (removing those nasty features and showing you how to do such things properly, you can contact me offlist at msummers at domain dot com (replace "domain" with "great-web-sights").
And by the way, editing outside of Dreamweaver is a very very dangerous solution that does NOT work splendidly over the long haul. Just wait until you update a template, and it erases all of the external edits you made several months ago!