I'm having trouble figuring out how to set a base rate.
If product type A (taxonomy) is present, i need base rate X
If product type B (taxonomy) is present, i need base rate Y
If product type A and B present, I need base rate Y

I can't figure out how to use either components or shipping rules to do this.
Any help or guidence on a direction to explore much appreciated, I'm lost!

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my final solution is documented here: http://www.drupalcommerce.org/questions/3773/accessing-product-line-item...