This depends strongly on the application. The more anti-dive on braking, the harsher the ride. For many years, the engineers at Ford tended to favor ride over anti-dive, resulting in cars that almost scraped the front bumper under heavy braking. But, I'm sure many buyers favored the softer ride and didn't complain. On the other hand, a stiffly sprung competition sports car might also have zero anti-dive. In this case, the low center of gravity and high wheel rates keep the car relatively level on braking.
So, I can't recommend an anti-dive percentage. Personally, I favor a low CG, stiffly sprung car and the absence of anti-dive doesn't bother me a bit.