[johnb]

I definitely overstated here sorry. Found the excerpt I was remembering in my copy of code complete "On a project that uses inspections for design and code, the inspections will take up about 10-15 percent of project budget and will typically reduce overall project cost".

So assuming the same payoff benefit (big if, but let's go with it) between PR style reviewing and more formal inspections, every engineer should be spending around four or five hours a week performing reviews to hit the sweet spot.