PHP + XSL + XML, Am I on the right track

Currently I have this site and one of the pages is one big PHP form. Basically you enter in the required fields and it spits back all the data in a table.

Now I have been reading allot about XML, and was wondering if I was on the track. My ultimate goal is to make the download the smallest possible. Now I have converted this current PHP form into several files. I am using the Idea's behind this example : http://www.w3schools.com/xsl/xsl_client.asp

Now I have :

File 1 : PHP file which just displays the form to enter in the data, plus some JavaScript to call for the xml file.

File 2: Pure XSL file which handles the table layout

File 3 : XML File. This is coded in PHP and depending on what it passed determines what XML output

Now I got it working, and have reduced the downloads by about 40%. Before the normal PHP output was about 300K, vs about 180k I am getting now. But this is requiring the Client side to do all the XML parsing. I know all people viewing this site are using Internet Explorer.

I still need a HTML Form, which is used to gather the information. Now am I on the right track, or should I look somewhere else, for better examples.