This simple requirements has alluded me. 

I have setup Books as it is the only place I can produce a quote correctly for AU with GST and have established a Sync between Books and CRM with 2-way of the items / products (I really wish Zoho would use the same label for the same thing across its apps consistently). The update to CRM and back to Books works fine but I don't see where I can sync the Tax rate I set in Books Items to flow thru to the CRM Product.

The field mapping shown for the Item integration makes no mention of this.

What have I missed?