OK. Your case sounds like a job for a plain old RPM, without involving Patchmanager at all. Unless it also involves altering some QML files, but you did not mention that.

Basically, all you have to do is drop a few files in their respective locations and remove some existing files. The new files will be part of your installation package, removing existing files would go in you pre- or post-install script. No patching necessary.

To allow for a clean uninstallation, you will have to make a backup of the files you have removed. The simplest way of making a backup is to simply rename the files, preferably to something unique to avoid conflicts with other packages. The simplest way of renaming is to change the extension, e.g. ttf -> bak, but a safer way could be something like Roboto-Light.ttf -> Roboto-Light.ttf.Markkyboys-super-duper-cool-patch.backup. Your unistall script will then rename it back.

I am typing this on my Jolla in McDonalds while keeping an eye on the kids to keep them out of too much mischief so cannot devote more time to you but I will have a look at your code as soon as I can. Probably later tonight. Of course, someone can beat me to it by then