David's words on the subject are sufficiently vague to allow a number of interpretations. It depends where you measure the leg height from - the bottom of the arch? or the bottom of the heart? or some other measurement? And where do you measure bridge top? From the top of the heart to the crown? Bottom of the heart to the crown?
There is no formula, as it depends on the bass and the bridge blank, but generally, what you want to avoid is something like this where too much wood is taken off the top of the bridge:
(this is a picture of a reject
bridge from Upton repair website - it was taken off a bass in for restoration ... they were NOT responsible for cutting this one!)
I often see this, after an inexperienced person installs a bridge with adjusters - the inexperienced installer then wonders why the bridge is now too tall and trims the crown rather then further down the legs and feet.
So there is an important structural aspect to it, and then there's the "fine tuning" aspect, as the bridge is a HF filter. The audible effects of bridge shaping can be subtle and depend on the model of the bass, the model of the bridge, and the budget of the owner. And I don't dare start to generalise about it here