OK, I couldn't sleep, so I finished this up a few minutes ago. The glue is still wet, but everything press fits together so well, it pretty much holds itself together (except for the edge tiles that are only held in on 3 sides).
Doing this gave me time to think about the best plan of attack for my Prime 29.
I'm going to run the numbers a few different ways using QRDude, and see if maybe I can come up with something a little less time consuming, but still pretty useful for my surround sound needs. I may bump this up to 1.5" tiles and drop down to Prime 23 for example...I hate to cop out like that as I really have my heart set on a complex period, but I'd still like to get these two side ones done before the end of the year!
And if I come up with a plan that helps me produce these more quickly, I may just revamp my whole back wall with 2D diffusers, and make a couple extra for my "office" which is really just a corner of the basement with my computer, guitar amps, and a work bench for building guitar amps.