If you use a modern booster that mounts to the firewall, you will have to relocate your battery. Some owners/w power brakes have retained the original, divorced booster that's mounted on the driver's-side inner fender and plumbed it into either the front/rear brakes, but it will not accommodate all four corners.
That's one expensive master cylinder! Was it necessary, considering you have the OEM booster? I paid less than half that much for my Wilwood master cylinder, but it's not "compact." In order for the battery to remain in the original location, even w/o a booster, I had to install Wilwood's proportioning valve on the opposite side of the master cylinder, between the master cylinder and the engine. If I had OEM exhaust manifolds, I would be concerned about the heat, but the Sanderson headers are ceramic-coated (keep heat in) and they aren't as close to the master cylinder.
I simply purchased a dual MC for a 74 Maverick. disc front, drum rear. Tha has been my go to for disc conversions on a number of 50s and 60s Fords. I do not have PB on my '57 T-Bird. It stops fine. I also like to install a 2# check valve and an adjustable line pressure valve.