Well, a simple installation often has little to do with the size of the upgrade. I don't know your situation, but if it's within a company LAN, the size of the download is irrelevant. From your post I guess it involves a download over the Internet, so it may or may not be important to the users.

But trust me on this: if you want your users to have an uncomplicated installation process, the single best thing you can do is to make it one file they need to deal with. No directory structure, no requirement to have Perl installed, and most importantly, no module dependencies to deal with. This is especially true if your users aren't particularly geeky.

PAR works for both Unix and Windows, and it's possible to package many platforms in a single binary (but that will obvioysly increase the size).

/J