Re brmeyer135,
You are correct to point out my build could drop some weight. It is certainly not, strictly speaking, a "weight weenie" build. I appreciate your suggestions and any others you can think of.
I did discover the remarkably light weight Quaxar rotors. There are conflicting reports if they degrade braking performance. I would like to decide for myself by starting on the (heavy) Shimano rotors and then try lighter rotors later. Do you have an opinion?
In general for this build I am hesitant to accept significant compromise to performance (braking), durability, and comfort (saddle) if it means less confidence out on the trails, especially while racing.
There are certainly many races where I could run a rigid fork. It is relatively easy to change forks. Also nice to have a rigid to plug-in when it comes time to service the Sid so I can take my time and still have a rideable bike.
I did consider a Lefty. I like the design. It does seem to have advantages over a conventional fork: rigidity, as well as lighter weight. The requirement to run a special hub ultimately turned me away. The top-end Lefty is more expensive than the Sid. Plus, it would be weird looking! But I am sure I could get used to it.
I need to look into the lighter through axle you mention. What is a starnut?
Will likely keep it flat black. Paint adds weight!