I live in UK and have $400 AA transportation vouchers (paper) to use by April 2018. Would someone please confirm what is meant by this paragraph:

"These vouchers are also valid for travel on oneworldŽ itineraries (including oneworld affiliates that must be booked as a codeshare flight marketed by a oneworld carrier) where American Airlines or American Airlines codeshare flights (AA*) is the international carrier."

Does this mean that I can book on any flight with an AA codeshare number - or does the transatlantic section need to be AA metal. I've read conflicting advice online, and although I've skimmed through some of this thread, I haven't found a definitive answer.

I assume I need to book via AA (which often adds a bit to the cost, compared with the same flight booked via BA/IB, etc). Given the relatively low value of the vouchers I'm considering a Premium Economy trip from EU (DUB, ARN, etc) to East US (PHI, ORD, etc). I'd only consider West US if I could use Avios to upgrade to Business.

Thanks for any advice.