You know, if people are still making the fascias that must be spread to install them like OEM, they should cast the fascia a little wide so when you actually go to fasten it, it would be perhaps 1/2" wider that it should be. Even 1/4" wider would be a big improvement.
It is amazing how easy the fascia goes on if there is no bumper or inner baffle. Since the radiator surround is narrower at the bottom, you simply lay the fascia on the floor and snap it on. With the fascia on the floor, the supports are about 1" narrower relative to fascia. Then you simply "rotate" it up into position.
Takes 30 seconds to get it into bolting position.
I think you could even accomplish this w/bumper attached to fascia, however baffle prevents bumper from going to a lower installation position.
I'm back in PA and can now spend countless hours thinking about how to improve this situation. I still think there may be a clever approach. I think the key is installing it low and rotating it up. Maybe some rework of the baffle to let it rotate too may be the trick. Of course the studs sticking out from the frame rails require the bumper to shifted forward to clear them.
If the studs could be replaced with bolts, then the bumper could slide over the front of the frame rails with the fascia snapped on. Some mods would be required to do this - especially to keep the front frame rail shims in place.
I really don't like the idea of grinding the edge flange off the radiator supports. That is a stiffener and I don't like removing stiffeners.