I'd like to see information from The Wand Company on that.
As for the kit it's a bit of a pain to assemble. Definitely use your own tools, not the crap drivers that come with it. There are a lot of holes that are made to thread when the screw is put in and you can't get enough force to do it with the included ones. There are also a lot of small bits for buttons, sliders and other details, so don't lose those.
My issues are primarily with the arm cuff. The latch that looks like it is supposed to tighten the cuff isn't functional. It could be with modification, which I am working out. I have given this a pass already, but found that the lower buckle is pretty weak as is. The cuff also interferes with the holotape deck, and the deck is opened by pressing in two fake screws on either side and pulling down on it. It's a bit cumbersome and lacks that tactile feel cassette trays had on older audio equipment, so that's another spot I am looking at for modification.
No room for a normal rpi, but if you wanted to use an rpi the zero would be fine. There are other computer platforms that would fit. If you go for an MCU there are a ton of small options that would fit no problem.