This page has a chart that gives the cosine values for the different common hubs and cross patterns. The numbers in red in the chart are the COS(SAA) values for the formula. Values marked X are not recommended lacing patterns.
 
 
 
For example, if you have a 36 hole hub/rim set and you want to lace a wheel 3-cross, the COS(SAA) value would be .50. If the hub you are using has a spoke hole radius (HSR) of 30mm, you would multiply 30 by .50 and get 15 for the value of HSR x COS(SAA) on the formula. Don't forget that this value needs to be squared to complete it's part of the formula.