Thank you for responding so promptly to my question. For some reason I didn't get a notification from the Forum when you replied, so I'm just responding now that I found your response on the Forum.
As requested, I'm attaching a .pdf of the page with the arrowheads. They appear in the entry for Unita 13. I'm wondering if I should just use the arrowhead symbols $[ and $o and an embedded TN stating that's what they are. Since there's no explanation in print, this would be giving the braille reader the same information as the sighted reader. What do you think?