I have it setup as you have described (there are 5 holes per curved 'bracket'). Hope the pics below help to explain the current situation:


The fact that 1 curved bracket is shorter than the other is causing the angling. If I use both large curved brackets on 1 vent I can achieve horizontal slats, but then have two smaller curved brackets that are too small for the other vent to function correctly.
Must be getting closer now


The fact that 1 curved bracket is shorter than the other is causing the angling. If I use both large curved brackets on 1 vent I can achieve horizontal slats, but then have two smaller curved brackets that are too small for the other vent to function correctly.
Must be getting closer now

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