The first tine weeding pass is done about an inch deep immediately after planting. I planted the beans approximately 1.75" deep, allowing the tine weeder to remove all the weeds that are in the top inch or so of soil. Most importantly those that are in the row of beans. I can't get at those weeds once the beans emerge. There will be one more pass with the tine weeder, when the beans are about 4" tall. Then there will be two passes with a row cultivator.
I'm finding out that the technology is good most of the time, but it can go wrong. For several logical reasons there is a mismatch between the movement of the tractor, where the GPS receiver is located and the planter where the seeds are placed in the row. As a result, while the tractor is following a line I set to within 1/2 inch, the planted seeds can occasionally vary by 2-3 inches. This will become more of an issue when I row cultivate in the coming weeks.
The medium term low cost solution to this is installing a sliding hydraulic quick hitch that I can control from the cab. I'll need to put a camera on the area where the row cultivator is engaging with the soil/plant and then move the hitch digitally from the cab. New products and uses for them are coming out all the time but a single package that gives me what I need isn't here yet.