I took the Design and Rhetoric posters to the printers yesterday but they were unable/unwilling to get a dense black for the square. I have found an alternative printer who, hopefully, will be able to get the black as I want it. Short run printing can be so frustrating.
On the plus side, I have two test copies (with shoddy printing) that I now have on my studio wall. This has given me an opportunity to look at the posters at full size and evaluate the typography. The margin, at 15mm works well. The title, set in 90pt, works well and I am happy with the letterspacing on it.
Unica seems to have quite tight spacing, the tracking on the body text looks a little bit loose at full size: it was originally set at 30/40pt with 30 tracking. I have made a few tests with tighter tracking that I have printed out and placed on the full size poster. I have also increased the point size slightly to achieve a more uniform grey.
More information about tracking and kerning can be found here and here.
Update: Further proof that, sometimes, the more you look at something the less you see - I've just corrected a typo on one of the posters, just in time for printing the posters but too late for my Design and Rhetoric book.