I tend to agree. Also, even though I'm not a "correct or "numbers" guy, it doesn't make sense to start hacking up the car in case I pass it on to someone who is.
Yeah the larger radiator still adds surface area for cooling, and still adds more coolant capacity which also improves cooling. Sure, if you open up the radiator support to the full width you will get additional cooling at speed than if you don't, but realistically that's not when you need additional cooling on most of these cars. With a fan and shroud installed you'll still pull air across the entire core at idle and low speeds, which means you're using the entire core even if there's some of the edge that is obstructed from direct flow from the front.
On the 22" radiator supports it's also very easy to see where the 26" opening would be, because the lower part of the support that's welded on is the same for both supports. So, you can see that the corners on the lower part of the support are back from the inner edges on the 22", and inline with the edges of the opening on the 26" supports.
