Hey Tyler,
after ordering the blades I thought to try entering Ross lawnmower in an Ebay search and got this. I'm pretty sure it's compatible. When I had entered Wesco I only got a listing for two pairs from the same brand labelled for Wesco.
Postage is free and they're 50¢ cheaper than what I ordered mine for.
https://www.ebay.com.au/itm/NEW-Byn...-CATCHER-460mm-18-800-802P/123928228027?