I have the same carb and have worked it out for the most part, first off, have you read this?
http://ls1tech.com/forums/carburete...t-level-holley-tuning-serious-ocd-tuners.html
http://www.burtonmachine.com/documentationtechnical/
That power valve calibration sounds rich, 12.8:1 sounds more like it, it comes down to what your engine pulls best at. Idle A/F ratio is the same, wherever it want's to be smoothest at.
Have you bought a box of brass set screws? 6-32 8-32 and 10-24? 81-60 drill index with a pin vice? This way you can calibrate inexpensively.
If you haven't, do that first.
I'd start here, if you need help I can guide you. Start with the stock holley calibration from the 60's, go from there.
I had to dial back my idle feed quite a bit, pretty much EVERYTHING including airbleeds quite a bit. These carbs are setup for healthy big blocks as far as I'm concerned. Rich as hell!!!