At least OSX 10.3 compatible, however for these particular functions I'd think much earlier. Should work for all the earliest OSX's.

Functions like launch from installer depend on how it is scripted. The launch function I use after installation for the connection installers is limited to OSX 10.3. I use the application id number, example application file id "org.phex". Workaround is to use the actual program name and could be used dependent on OSX version. But the launch after installation function is not really important in my opinion, simply a way to finish off the installation process.

As for script installer size, notably small. Phex connection installer is 238 KB on disk (184,642 bytes) made up of: 49 KB Phex icon, 57 KB connection file, 45 KB 11 language translations, 57 KB applet, 4 KB CorePrefs, 8 KB scripts.
In comparison for the installer size of the 'other' Phex, it would be the size of the Phex folder 17,081,715 bytes (17.1 MB on disk) plus the above. To reduce size of the phex installer would require pre-zipping the phex folder and the installer unzipping via the OSX system which I've never done before & need to be done differently depending on OSX version. I don't think reducing the size by 1.7 MB (10%) is that important.
The actual process of Alias & Dock is purely scripted. I'd need to look at how to change the icon of the jar file however, if that should be beneficial. Otherwise the icon in the Dock uses the cup of coffee/tea icon with the word jar written below it.


A side-effect of the jar file not being an application in Mavericks is the icon in the dock is set to the right-side. No ability to shift it to the left of the divider unlike on Snow Leopard 10.6. . (I didn't like the lesser user options for Finder on either OSX 10.8/9. I hate that you cannot open folders separately. This would slow my work-flow down quite considerably.)

* Edit: Just realised that when opening Phex via the jar file in the Dock, another java icon shows in the Dock. This java icon is from the java executable from /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home/bin.
Probably not important that a separate executable java icon shows? I can phex iconize the jar file to at least show it belongs to Phex as the image shows.