I recommend picking a random sample of commits to review more thoroughly by hand in parallel with the harness review.
That way, you get the opportunity to measure how many and what kind of issues your harness method misses, and with an estimation of their cost, you can make an informed decision about what magnitude speedup pays for the change in detection rate.
That way, you get the opportunity to measure how many and what kind of issues your harness method misses, and with an estimation of their cost, you can make an informed decision about what magnitude speedup pays for the change in detection rate.