Information on optimizer

Dear Experts,

we are currently in throes of implementing SCM7.0.

The question I have is as follows:-

Does anyone know of a note or have some information that explains how the optimiser plans and schedules planned orders in SNP,which calendar takes priority the calendar assigned to the resource or the production calendar assigned to location master. THen the scond part would be how and when does the calendar assigned to the location master take priority

cheers

Paul