Has anyone tried a rubberized coating on older Klipsch tweeters?


I’m restoring my RF-3 ll speakers. They are VERY bright compared to my RP-600M pair. I’m thinking of trying a rubberized coating on the surface of the horns, any thoughts?
aburnhamuu
I bought sheets of dampening material used for sound proofing autos and placed it all over the exterior of the horns. I found the results pleasing. Toned down the harshness of the highs. 
Not tweeters, but I have used a product similar to dynamat,  peel-off rubber like sheets meant for this purpose on the outside of the horns on my Epic CF-4's. I did 2 layers and it was effective, but I wasn't having an issue with brightness, I just wanted to make it more dead, and to compensate for the fact that it's plastic, not thicker wood.