I’ve tested v.1.1 of your Designer and I think I’ve found a few Problems/Bugs.
1: I’ve got no clue how to add Redists to Designer I found no ‘add’ Button like ‘add Shortcut’

2: I’ve Enabled all Options in Media Task, but got Problems with Slideshow and Background Music during Installation.
The Installation starts with Video, Problemless (Good Idea using .bik Video b.t.w.), but the Slideshow won’t Start after the Video and the Background Music is complete Disabled. Also I have a Text on Small Installer who should not be there (red marked).
At the End of Installation I get a Out Of Stack Range Error
If this are Bugs, please fix it.
If I have made something wrong, please tell me.
Thanks.