Every time you start the script it will go through an initial set up process where it opens the bank to determine which items you own, and it will proceed to buy the missing items after that from GE. After it opens the bank, it will print in the logger a list of items that are needed and then a list of items that are missing, as well as the quantities for each of them. You can open the logger from the button at the bottom right corner of the client and check item requirements for any quest or list of quests this way, and then stop the script after it prints the desired information in the logger.
Thanks, looking into it, will have a new version with bug fixes shortly
Most likely another dialogue update, will push the new version soon