I removed the pilotone from my IIC; it looked like it had been damaged at some point in it's life and was causing drag.
Arri did make a cover for the hole if you wanted to remove yours, I'm sure Mr. Broda would have one if anyone does. But if it works then why bother - who knows... maybe someone has an old nagra sitting in their closet (good luck finding the cable).
Nice flat mount adapter by the way, looks like you found a good set-up.