This is the greatest free (almost) modification ever! It took me about an hour and a half in total and worked perfectly on the first try. I used a sheet of 22 gauge steel purchased at Pep Boys for a couple bucks.
A few observations on the process:
1. You don't need to remove the shaker. The IAC is accessible from the passenger side without removing anything else. Two 8mm bolts.
2. My car is a 5 speed and I made the smaller hole 9/32. The other hole is identical to the one in the gasket. No problem cycling the A/C compressor with that size.
3. Be sure to deburr the edges of the holes after drilling/grinding to ensure that no junk gets sucked into the engine!
I noticed no difference in the amount of "burble" on closed throttle deceleration. The surge felt when engaging the clutch at low throttle position is gone!
Thanks, Mach1Canuck, for posting this!