When you exhibit at the show Ken are you intending to have the subs there too?I've had my Opals apart and will pass on what I learned and have done.
First, I had self noise on one speaker, a low level of hiss/hum that could be heard a few feet from the speaker. I added a ground wire from the contour board in the front half of the cabinet to the grounding bolt on the rear half of the cabinet. 70% or more of the noise went away and I now have to be very close to the drivers to hear anything.
Second, I added a pair of high level outputs, to connect a sub woofer to each monitor.
Both these mods can be seen in detail on my blog here: https://www.jkwynn.co.uk/Opals/Opal_01.html
I would be very interested to hear them