AFR misleading? Plugs tell a better story?

I am installing a 4 wheel, 6 piston calipers, complete Wilwood disc brakes system, including going to a Wilwood master cylinder.
I'm keeping my brakes MANUAL, and this new system is not a "budget" setup by any means. I'm keeping manual brakes because I prefer actually being able to modulate my brakes, rather than them being more like an on/off switch. I also know there are ways around having low vacuum and how that's bad for power brakes, but once again, the feel of manual brakes is my preference, and that's in a 70 Roadrunner, so more weight to stop than an A body.
Short version: unless you have leg weakness, I'd say don't hesitate to do manual brakes. More room under the hood too!
Thanks for the info and good to hear. Going to give it a try. Either a 1” bore or 15/16” For master cylinder.
Aluminum Master Cylinder Part Numbers and Data