I have a 505" with a 231/239 @ 0.050 Voodoo cam. I'm like you...I wanted a 'nice' idle (which is very subjective.)
I just got it running for the first time today. I have a lot of tuning to do before it is as good as it could be.
But for now it's got 13" at idle, with only 10d of advance at idle.