that looks nice!!
There must be any solution for a wider valance for cars with overriders
Cain at Wolf Performance is modifying my overrider mounts to allow fitting of full valance with aperture whilst retaining overriders. Something like this although think it will look better on a Roadster with standard number plate mount to reveal aperture.

The other solution is to fit the full bumper mounts which require just a circular clearance hole in the valance, then modifying each overrider to work with the single threaded hole mount.