As equal as possible is usually better. People can’t help but read motives into anything other than an equal split, and it will create ill will between siblings where none need exist. It will always be there.
The fact that one child has more money is neither here nor there. Each chose his life’s work, each made his decision (and each is engaged in honorable work) and in most cases its not appropriate to account for that in the will. There are exceptions, but as a general rule you should not use the will to settle grievances and you should try to treat your kids equally where possible (even when one seems less deserving than another). I’ve heard of people using the will to settle a grievance and its not pretty.
An exception is where you’re dealing with whole property rather than money, where the property is not going to be sold but left intact, or in the case of a business that is to be run by one of the kids. That gets more difficult, because some things can’t be divided. Some businesses can’t be run by just anyone, and some kids may have no interest in the business.
Amen, each child chose their own path in life knowing how much earning power the job might provide and have to live with the consequences or change the situation if they aren't happy with their current jobs.