Reply To: Reference notes to displayed expression
Thank you for your question and your clear example attachment.
The Nemeth Code does not address format for remarks (sidenotes or editor comments). The format you are asking about is one borrowed from the Chemistry Code, Section 2.3 (3) which a lot of transcribers like to use. That rule states the following: "When remarks, conditions, or explanations appear with the [displayed/linked expression] start them on a new line and block this material six cells to the right of the anchor margin."
Your rewording "4 cells to the right of the linked expression’s runover" is the same idea but note that this is a *blocked format, so the runover to the remark you have shown in simbraille should also be in that same cell.