The best way to go is to buy a system. Tell the supplier what you want to do. IE: disc front & drum rear with the booster/master mounted under the floor. I have done several of these and used a 8" dual diaphram booster with a dual master and a proportioning valve. My supplier installs the residual valve in the MC.
Lots of opinions on this subject but this has worked best for me and my customers are happy.
Fred


1956 3100 Pickup/Red/350/3sp OD/PS/Disc Brakes
1957 Bel Air Sport Coupe/Red/355/TH350/PS/Disc Brakes
2017 Silverado LT Single Cab SB/Black/5.3/6 Speed Trans
1947 Willys CJ2A w/F-Head engine