Hey Jerry!
Good to hear from you. I wish I could say I was using those, but this is all based on an oxygen sensor in my exhaust that's hooked to a mixture gauge. I just drive around the neighborhood watching the gauge.
Test drives before and after drilling did not indicate a significant mixture change. It might have been slightly richer on startup, but it only took 1/4" turn of the mixture screw to restore original idle mixture ~12.5
I just tried drilling the upper idle port itself and will do another test drive after re-assembly
