But when it is autorun it goes to whatever size the browser window defaults to. In almost all cases this is fine but it would be even better if I could just get it to open in a 640x480 window.

Give the file a name, save it wherever you’d like, and later you can open your notes in any browser. Even Internet Explorer will open notes saved as HTML, and you’ll also be able to edit them ...

So for example, if you want to switch your default browser to Chrome, you will have to specifically change it 11 times, for HTM, HTML, PDF, SHTML, SVG, WEBP, XHT, XHTML, FTP, HTTP, and HTTPS files.

Make Firefox automatically switch to newly opened tabs by opening the "Options" window, clicking "Tabs," and then enabling the "When I open a link in a new tab, switch to it immediately" option.