A:Answer Hello, Peter,
I had GEEK Squad folks install my TV, so I don't have a direct answer to your question.
However, I do have some thoughts.
I peeked behind my TV to see how the wall mount was attached to the unit, because the screen itself is so thin.
I am not familiar with the SANUS wall mount, so I don't know how thick the metal is where the screw holes are located. If the metal is relatively thin, then it seems that the 12mm (1/2") screws might do the job, provided they get a good bite into the back of the TV. The 35mm (1 1/2") screws seem like they might be too long for going into the back of the TV.
That being said, since I am definitely not an expert, I encourage you to consult with either GEEK Squad people or with the SANUS Customer Service folks just to be sure.
This is a pricey TV, and it is not worth trying to guess. (IMHO)
I'm sorry I can't be more helpful. I wish you the best of luck.
Best regards,
Gadjo