Experience with applying Kilmat to Cornwall IV Horns?

I have a new set of Cornwall IV's. I came across a few videos that showed the application of Kilmat sound deadening material to the back of the Midrange and Tweeter cones to improve SQ and "soften"  the (sometimes and rare higher volume) high end from the horns. Curious if any if the wise Audiophiles on this forum I have grown to trust have any personal experience with the SQ results of this upgrade, or if its not a benefit. 

Overall I am thrilled with the SQ of these speakers, but always looking for any feedback or improvements to my system. 

If it matters, I am currently running with an Innous Zen Mk3 / Denafrips Pontus II and Luxman L-509X 

Thank You!!