The radiator mount looks good,you shouldn't see any flex induced problems.Just make sure to isolate the radiator from vibrations,that would be the killer,the rubber mounts should be ok,make sure to set the radiator into rubber as well as wrapping the upper mounts.

As for the front mounts theres not much wght there(depends on where you mount the battery)so maybe some simple brackets off of the outer corners of the "stock"radiator support to the inside of the frame,maybe use some poly spring bushings in a tube attached to the inside frame rails w/2 tabs??Just an idea.

It's looking good so far.

Bansil