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.