How much does the highest salaried person make? Whatever % would leave that person with 200k/year sounds good. No one needs more than that amount.
So you want a marginal tax rate of 100% for income in excess of 200K per year?
Sounds like the Occupy plan. A hard cap on income from all sources is needed mathematically to achieve the wealth disparity reduction they espouse.
It would be a great way to turbocharge the barter system.
On a side note, when Ingmar Bergman realized that his marginal tax rate in Sweden was 101%, he emigrated.