Definitely line up in your boarding positions. Have the 3 boarding at B38, 39, and 40 save 2 rows between the 3 of them for the others that will board at 51, 52 and 59.
You will be fine. I wouldn't spend another brain cell worrying about it.
I have never had more than 2-4 people on my flights to Orlando in the A1-A15 section.
Please let us know how it went OP!