I have totally refactored the ui.qml file to tidy it up cconsiderably and to make it very much easier to create new ones. In the process I discovered the thickness error and corrected it.
I have also added the option to colour the reticule and to have the scope position off-screen.
The new ZIP file, which should replace all the earlier ones is here:
webvfx_sniper_scope.zip (17.0 KB)