what would be the best way to wind a homemade transformer for this circuit here:

http://www.maximintegrated.com/app-notes/index.mvp/id/1923

it calls for a 1.2:1 ratio with center taps on each side. i have several toroidal cores as well as ferrite rods. im a little lost because there are so many variables: wire guage, inductance, core Al,dc resistance, loading, etc. there are a lot of different ways to come up with 1.2:1. what would be the best and easiest route in your opinion? thanks in advace!

 

The app note gives details of the transformer:

Consider a typical toroid such as the 40603-TC from Magnetics, Inc. (0.125" thick with a 0.230" outside diameter). For 6.8V inputs this core should have a 48-turn primary (24 turns on either side of the CT), which yields a nominal, end-to-end primary inductance of 8mH. The secondary can be scaled for any reasonable output voltage required. Forty turns, for example, (20 turns on either side of the CT) delivers 5.2V minimum as required by the linear regulator for maintaining a regulated 5V output.