i've moved this post to our Server Admin section of the Community where you are more likely to receive a response from someone who may have done something similar.
To determine dimensions and measures, you will need to download the .twb file for the workbook. This can be done via "tabcmd get". To analyze the workbook you either need to parse the XML structure, or perhaps use Inteworks' Workbook SDK. To export the workbook with various URL params, you can send an http request that appends ?:format=pdf and then further appends the filter values. See List of Embed Parameters.