Made some more progress during the last few days. We got the upper arms pretty much finished and mounted. There's still a lot of frame bracing required around the arm and shock mount members, but it looks pretty straight forward to fab.
Everything was modeled up in SolidWorks ahead of time, but there was a lot of last minute changes to the design, so I was pretty worried about the final product. My worries were unfounded, it turns out. We've got a nice camber gain as the pieces move, and I have a lot of adjustability. I can dial in +1 to -8 degrees of camber and 0 to 8 degrees of caster. With a few degrees of caster and -1 degree of camber, there is essentially zero bump steer, too.
We did have to modify the miata spindles a bit more, however. Besides reaming out the upper piece to accept the larger ball joint, we had to tweak the steering arms a bit to better align with the steering rack. We basically heated up the arm and then took a large wrench and nudged it up into alignment. Let it cool down slowly and its good to go. Nice forged miata spindles let you get away with stuff like this
The steering unit is a Sweet Engineering assembly. It's gonna be tight feeding the steering shaft(s) up to the wheel, but it looks doable. All in all it's coming together pretty nicely.