Blocks bases are professionally machine lapped this time on a proper lapping machine. No hand lapping involved. Extremely flat, especially around the CPU contact area (defined as a 1.5"x1.5" square centered in the block), and outside of the abilities of my machinist's best physical tools to measure which are good down to around 5 microns or 0.0002". I don't possess or have access to a set of optical flats. They are even flatter than some of the best results that I was ever able to achieve by hand though, with that being subjectively determined by a basic reflective grid test.
Was able to get the professional lapping done due to the decreased machining costs on the block itself as compared to the Cascade.
Finish on the block's bases visually looks like this:
Machine Lapped Storm Base
with a smoky satin-like finish.
For those offended by the lack of a mirror polish, do not be duped into thinking that a mirror finish
necessarily equates to flat:
Mirror Polish Finish (left) vs basic hand-lapped finish (right)
Left Block
Right Block