She bought the wrong size, so she's got no reason to be pissed when you tell her they don't fit. On the other hand, she would be pissed if you slapped something together and try to pass it off as her gift. Women hate it when they think you believe they are too stupid to notice stuff like that. Not saying don't make the covers, just forget the part about her never knowing the difference.
"Hey, I finally tried the Jets seat covers and son of a vandruke, if they didn't fit!?!?! Bummer, I know. I found some that do fit though, I was thinking about custom making them with Jets logos. Maybe you can return the ones that do not fit. I truly appreciate you getting them though." Done. Literally, not worth lying about.
