First off, loving the studio - you must have mighty nimble feet.
2nd, have not bothered with EFI's profiling - using the RGB path, and Profiler to generate profiles. Learning curve was no worse than proof master years ago, and documentaion for using the RIP is properly written (unlike several other applications I could happily curse, and use daily). A RIP is a productivity boost, as once set up, you have queues that require no messing around with driver settings, and continuosly saves a log of outputs, saving (me) from keeping a written track of every detail of print outputs. I'm using EFI express designer edition - came with my first Canon, and they gave me an upgrade to Designer with the second one. Nesting is good, being able to add job tickets, and set offset of them, as well as trim lines, is a real boost.
Regarding the print longevity, that is the biggest issue. I've been (lightly) looking at eco solvent and UV curable options, and it seems that the straight CMYK sets are often rated for 7+ years outdoor (could be Texas, or Dubai), but that some of the white / spot options are not rated as long. I've read things in the past from Scott Martin about taming and controlling the quality of output from grand format printers, and there are a couple of production houses here in London, who bridge between graphics and art production, so I'm sure that there are inksets that will reach a level of 30, 40, 50+ years interior display.
If the Epson inksets have sufficient life expectancy, then the productivity boost of moving away from spraying would be huge. Even if you decide to cheat, and get a vendor / consultant in to set up a RIP, and PC... I think that 80600 could seriously reduce production times.
We've recently moved into what were office buildings, and every so often, I look up at the grid supporting the suspended ceiling, and think about how that would make a real good static drying line. Every time I have a big show to put together, my biggest bottle neck is landing zones - end up taping prints around the walls of the corridors and offices.
These look to be wall decor, rather than long term gallery art, 135 pieces could cover a fair part of the purchase, install and set up cost. If I had the space, I'd be likely to jump.