British company Reed Aquatherm has some spray decks that will match your cockpit size: it would be 61 cm by 43 cm in their fitting range which would be the size they call “Ocean B”. They note that this will fit Anas Acuta and Pintail boats, which might be helpful to know in cross referencing other brands of skirts. You might have to order from a UK company though Reed has a few US dealers.
https://www.chillcheater.com/decks/aquatherm-spray-deck-with-adjustable-waist
Topkayaker sells a spray deck for the Anas Acuta (26" by 18"). A half to and inch on each side should not make a difference in fitting a stretchy skirt. Are you measuring the outside of the coaming?.:
http://topkayaker.com/index.php?main_page=product_info&products_id=1672
You could also consider having a custom tuilik made – this combines a dry top with an attached spray skirt. Paulo Oullet makes quite nice ones to your measurement.