[link=http://web2.murraystate.edu/andy.batts/ps/fuel.htm]Here is[/link] a fuel mixture calculator I wrote in Excel to mix two fuels with different nitro and oil levels and add extra castor if desired. It also allows you to specify the synthetic/castor blend. The calculator is designed to yield one quart of fuel.

I fly 1/2A and don't mix more than a quart at a time - I just got tired of doing the calculations by hand.

andrew