You can damp the tweeter and mid with bits of black gorilla tape stuck to the outside of the wave guides. It doesn’t take much, and you wont be mucking around with repeatedly removing the front panel to make adjustments. The black tape is pretty much invisible unless someone gets up close.
Padding the interior and damping the bass basket never worked for me in my situation. It over-damped and deadened everything. The only other thing I did was to insert a a stick-on vinyl footed 18 lb lead weight through the front ports to rest on the bottom plate of the cabinet. I would try these things before spending lots of money on room correction.
My Klipsch is a Cornwall 4.