the logic of setting shipping and tax rules in eCart 6 is no different from previous versions.
for different shipping rates by product type such as CD, you need to have a column for itemType
then in the shipping you can set the rule for each level:
triggers:
"Items with a Specific Column value"
Number of items where "shippable" has a value of "1" is ">" a value of "0"
AND
"Items with a Specific Column value"
Number of items where "itemType" has a value of "CD" is "=" a value of "1"
Charges:
Falt Rate: 5
and create additional rules for each level