Best glue/adhesive to use to reseat/reseal seat backing to plastic molding?

Spray adhesive.

Marine Adhesive:


Use this for permanent repairs on my boat, shoes, other stuff. Put it on, clamp, once it dries/cures it ain't comin' off of anything.

I accidentally spilled a couple of drops on the concrete driveway and didn't clean it up promptly. Those drops are still there years later; even pressure washing won't knock 'em off.