The reason the MAC whitefaces don't look that great at night isn't due to MAC's design. It's due to the design and location of all the light bulbs behind the instrument cluster.
When I installed mine I took everyones advice and peeled off the old guages and cleaned the cluster as best I could with goo-be-gone. I then stuck my new faces on, installed my needles, and reinstalled the cluster back into my car. From dusk till dawn the MAC whiteface guages look great! However, during the night, the MAC's light up poorly, not because of the guages, but because there are not enough light bulbs behind the cluster to properly enhance the visibility of the cluster.
You're only resolve is to find a Cobra whiteface from a true Cobra Mustang as those were originally whitefaces and the bulb pattern behind the cluster is different.