Paint to match white upholstery

Hi All,

I have a 69 Barracuda convertible and reupholstered my seats in white from Legendary, and have the door panels/sunvisors to match. I'm trying to figure out what shade of white to paint the side panels, as I'd like to avoid the dreaded multi-color white interior. I bought a can of SEM Super White, which comes relatively close, but doesn't really match. I'm sure others have had this dilemma, too. Has anyone out there redone a white interior with Legendary's white and found something that matches well?

Here is a pic of a piece of steel that was primed white and then painted over with SEM Super White, and on top I placed a scrap piece of the Legendary white upholstery. You can see the Super White is much lighter.

Any suggestions would be greatly appreciated!