Hi aerosam, there are a number of articles on the web regarding mcyl sizing and pedal ratios which should help, basicaly a smaller diameter mcyl will give you more brake pressure with slightly more pedal travel and you shold have a pedal ratio of about 6 to 1. Here are a couple of interesting articals; http://www.hotrodheaven.com/tech/brakes/ and http://www.markwilliams.com/braketech.aspx . Cheers Brendan