We have to write an install for our product, so I’m rediscovering the spotty MSI documentation again.  I just wanted to link to this page for formatting options for properties.

For example, if you want to get the directory that the component “web_core” got installed to, you can use [$web_core].

If you would like to get the path to a specific file, you would use something like [#fileid].

There are more formatting options available, but I tend to use these the most.