MAK, the problem with what you seek is that the exact same tire can take on different dimensions as to its width and height depending on the specific rim that it's placed on. You'ld be surprised how much it can vary.
Speaking in generalities, Continental at times tends to overestimate the size of their tires, so often a stated 28mm tire will often more times than not measure 25/26mm. It's always been assumed that this is done for marketing purposes so they can advertise their 28mm tire weighs less than the competition's 28mm tires.