Good morning Kyle,
I contacted the agency with the same questions and got this response:
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I have a Summary of Advice for UEB Technical handout and Spatial Problems Rules and Advice slideshow that was given by Kyle DeJute (National Braille Association UEB Technical Committee) at a conference. This is what is on one of the slides: "As a guiding principle, if print alignment can be reasonably reproduced in braille, then follow print for the sign used to indicate omission. If print alignment cannot be reasonably reproduced in braille, use a visible space for each printed object that indicates omission."
I think because of this advice that I would use a question mark, a square or blue box (example: dots 4,5,6; 1,2,4,6; 3,4,5,6; 1,4,5) if it fits. If not, I would use the visible space symbol (dots 3,4,6). I like how you did the question marks!
Thanks!
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I'm checking with you to see if this method is still valid.
thanks, Fred