Tighten our paint prevention timings to provide more responsiveness while keeping smooth page transitions.

Proper balance is not easy to achieve, as preventing the "white flash" is just part of the equation.

Layout stability, allowing early readability, is another important term - as is bandwidth. Engines with aggressive timings would get an unpleasnt, jerky feeling we want to avoid.

We'll use subtly progressive timings to get a good compromise.