Purchase Order Saved search amount paid/remaining

Hello there, i would normally ask a query on here with at least an attempt at a saved search, but this has me stumped, i'd like to create a saved search for all Open POs with amount paid and/or amount remaining to pay, and if possible would like to include the Customer: Project Field also as we use this denote which project the PO pertains to, have taken a look on Suite Answers etc, but no luck at all, would apreciate any advice or pointers in the right direction, thanks for your help.