So do you want to try another method?
Open the grill and put a cut of soft density sponge. They smoothen upper mids - low treble region. Did this with so many IEMs and sounded great, smoother than micropore tape but not as muffled. Depends on the needs.
Micropore tape is additional damper after sponge mods for me to tame 3khz if really needed
I learned this from many Sony earphones. Be it cheapo MH750, MH755 or go up until their flagships EX1000, my current fave IER M7. They always use sponge for their dampers on nozzle. I guess they tuned more aggressively then smoothen out with sponge.
Just remember using low density sponge that have lot of cavities, or else they will be muffle entire sound. Easier and cheap ones are "animal sponge" on 1 dollar shop or daiso in japan. They look like a capsule and they will pop up in hot water.
And secondly, dont cut too big, if you need to squeeze much to get them in, they are too big. Supposed to get inside nozzle effortless so they still have empty space even a little for air flow way.
Example of my latest IEM KZ Z1 that have edgy and boosted 2khz, 5khz, and 8 khz. Did try with micropore tape but still sounded harsh, but with this i can crank up on high volume (of course im using EQ to fine tuning the Z1 since they are very v shaped from the start)
Did these with Spring1 Mod, KZ IEMs, BL03 mods, etc
Ask me more if you need help / guidance
Edit : these are animal sponges