Can't you just edit>duplicate?
I would do that, strip out the content of the original page and then save that as your third page.
I've never used templates. I don't like them - it's personal. for a ten-page site, I'm not sure it would be worth it anyway. If you are using CSS to style and position and not tables (I hope so), then you will put that in an external style sheet and link to it in each page.
There are basicly two methods, firstly the template method you have already tried, and secondly the "includes" method. Some people use one or the other, some people mix the two. I use only the includes method.
The includes method can be done in several ways. The PHP language has it's own method of doing includes. That's what I ususally use. You can also use the SHTML method. With the SHTML method, the material you wish to include is put in a normal HTML file, then in the file where the include will be put, it is done like this:
<!--#include virtual="../includes/banner.html" -->
. . .and the pages/files must have the shtml suffix, not html. That informs the server that yo are using server script in the file.
I don't use Spry menus (or spry anything) so I can't suggest a reason you encountered a problem with it.
Herp derp. Such a simple solution. I totally didn't even consider that.