Damage range <-> crit conversion?

Heroes perform badly on crits - Combo Attack (+120% iirc with 10 orbs & hypers) is additive with crit damage so they do way lower crits than most classes. Basically regular hits are 220% and crits are 250~270%.

I know Crit is less useful for Heros than for other classes because of Combo Attack, but I don't really know the numbers. That's why I asked what Crit % and Crit Min Damage do for Heros.