""I can lean out the idle more but it makes it more prone to stall on braking.""

Radar,
I found this same problem when I tried leaning out my in D idle A/F into the mid/high 14's. I would slow down to a stop and my idle would start to fluctuate and I would have to kick the accel pedal to keep it going. After a few stops I richened it back up into the high 13's and it quit doing this.

Good point!