CMYK as easy as 123 in Corel X7
An easy step on how to CMYK separation in Corel X7
As you can see the default settings is C=15,M+=75,Y=0,K=45
You can experiment on that angle as long as the image is looking good
but another angle commonly use to minimize moire is all angle is the same
as for the Corel Draw you can use 22 all angle.