Thanks for chiming in, everyone. I had no intentions of getting rid of vacuum advance. I even had someone nicely pm me just making sure I had no intention of going down the road of post #7 for my application.
Thanks, Cliff, for posting such a high detailed unpacking of timing. I've definitely read a number of your posts on the subject and am trying to get it set up using your experienced advice. My main question was whether my vacuum advance and quick timing curve were coming together too much in that small window and whether only one or both should be addressed for my application.
Interestingly the springs that were originally in this distributor when I got it were super light and lots of advance was coming in at idle. I swapped them with another distributor I had which gave the curve noted in my post. Now comparing them to a third definitely untouched stock distributor, the stock springs are thicker still. I popped one spring on and it's still too quick so later today I will swap the second stock spring on and see where it is at. I also took the vacuum advance off that stock distributor and have limited it to half the travel so I will pop that in too and see if it's around 10 degrees. Hopefully that gets everything dialed in.
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