Thanks for the responses!
@Honda: I've been trying to get both to 5GHz (167x30), mem at 1670MHz but so far, no luck at up to 1.55vcore/1.4vtt/1.86pll/1.28 qpi. I keep getting BCCode 135 which doesn't seem to turn up on searches so far. The best I've gotten is 4.93GHz and the A515T seems to require lower volts than the F729.
I'm under water so I'm not sure how high I ought to push vcore.
@Sam OCX: Thanks! I initially leaned towards the F batch, esp. given the performance of 3005F720. But I have the F729 which is less well-documented, and the single screenshot of 6.3GHz on the T is giving me pause.
Will keep trying.