Another vote of confidence for Martin's calcs. Eventually(!) followed his advice properly on my car when I had it and the braking was excellent. For a long time I had it with way too much front brake compared to rear. Was a bit of a mish-mash of bits, but it worked great in the end. Can't recall the numbers I used now but it was what Martin told me to use. You certainly do need a good dose of rear brake capacity.