So sorry! I forgot to mention those commentaries. Yes, the commentaries will observe the same right-hand margin as the rest of the text within the line-numbered format. I see this commentary as a blocked paragraph. I would have a blank line before and after and keep that right side margin.
I also forgot to mention the TN. Yes, indeed have a TN at the beginning. I think all you need is to explain that the verse numbers are centered above each verse in print and shown at the right margin in braille. I don't think you need that additional information in the TN about the 3 blank spaces because there won't be any here since the line number is applied only on the first line of the verse.
I agree with you also about the ease of reading in this format. It also makes it easy for the reader to distinguish between the verse and the commentary.
Thanks for this very interesting question.