It does sound like you have a simple adjustment issue. I adjust the brake shoe to the drum where it just drags as you spin it. Backing and hitting the brakes has never worked for me. DOT 5 is fine to use if all the parts are new. Sounds like you have 50% new. The brake hoses and wheel cylinders should be changed at this point just because its the safe thing to do. Those are cheap parts that will make your vehicle safer for everyone on the road. Many will poo poo the DOT5 fluid, but I have been using it in race cars and muscle cars for years. Never had a failure. Just my 2 cents.
1969 x-77 Z/28 orange/ white stripes, named by my daughter "Clementine ", M-22 close ratio, 4:10 12 bolt, CE 302. Hugger orange with white stripes. White standard interior. Restoration complete May 2018