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Well I actually kept the 2012 display, so I didn't shave off the plastic part or do any of that business. I would just say take your time and don't rush anything and do it evenly on both sides and you will likely be fine if you are attempting to fit the larger cable into the smaller slot.
I also used a 2012 display with a 2011 motherboard which is probably why I did not have a problem with the video connection.

@theapplehead , I hope you are successful.
 
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