Well you've done a lot of work on this -- good for you!
One thing about the hydra boost.... it's a lot of plumbing and it hangs way off the firewall.
No real need for "power" brakes... a good Wilwood manual master cylinder will work just fine. Just my humble opinion. ABS also makes an electric booster that works similar to the hydra boost but with MUCH less plumbing and you can mount the electric wherever you can fit it. They have several systems including under floor. I saw this briefly at their booth at Grand National Roadster show last week.
http://www.abspowerbrake.com/ehpm.html