Nice lookin' epoxy wall Joseph! That's just what I'd do on that side. There's another possibility I see. Test it as is, and if there still isnt a boost in off idle torque-- then you could fill the other side too. Looking at the area between the right side of throttle shaft, going back towards the large cavity you dammed off--the material is pretty deep/thick.
There's that slot that opens to the bore over throttle shaft end. It's probably a vacuum passage. I see a way to do an IAC trench using that slot, the trench would go thru the material connecting that big area you just dammed up to that narrow slot. If that existing slot is a vacuum passage, then I would simply do a notch into the bore from the slot, at that last cross-notch across the slot. I would cut a new IAC air trench from behind the JB dam to connect to that slot's original bore entry, and fill in the area of the slot between the existing bore entry and it's new one. This new IAC trench would flow less air than the factory IAC setup, with it's huge "spillways". If this IAC trench doesn't provide enough air to support normal cold start fast idle, it could be carefully enlarged to add more flow. A 1/8" drill bit will do it as Ron showed us. This is all predicated upon if the base gasket is a flat fiber material type not a silicone O-ring, AND filling in the other smaller IAC opening.
By doing this, you will be creating a full-width artificial throttle bore wall for the Groove to interact with, removing the IAC airflow/turbulence from the Groove's area, and still preserve some IAC airflow potential, and preserve that vacuum passage too. All this should help your Groove a lot. IF the bit you Grooved with fits tight or isnt completely "deep" maybe slightly clean up the upper rounded Groove area...
Just my 2 cent's worth... BTW does this Honda have Constantly Variable Transmission, is that what CVT stands for?
Tracy G