A correct to my earlier post.
Brake balance is generally to the front even for single seater race cars and mid engined cars. Front/rear weight distribution will affect the amount of braking bias but this will always be in relationship to the weight distribution.
Brake bias using valves and adjusters is always dependent on the braking surface area (pads and shoes) remembering that the effectiveness of calipers is dependent on caliper size and the number of actuating pistons. Brake linings are notorious for their poor contact area especially after a reasonable amount of wear.
