If you do your prep work correctly and use the right stuff, the wax portion itself should be a breeze. In fact, it probably takes me the least amount of time when comparing to washing and polishing. Polishing should take time. You're basically correcting imperfections in the paint. Cheap waxes contain fillers, some polishing and cleaning agents. Depending how much prep work you do, a lot of this isn't needed. Which will add to how much "haze" you have to remove and the amount of dust that results from it. It also depends what kind of wax you use. A carnuba based wax or a synthetic wax.
I realize that really didn't answer any questions, but people here have the right idea. The time the wax should stay on the car depends on what the manufacture says. Every brand, every type is different.
If you want max shortcuts to cut on time, use a synthetic based wax like NXT or TurtleWax Ice. Skip the polishing. Most of these waxes are very forgiving and are a lot easier to clean up than other OTC products. Again, don't know how mothers ball would help you in this case. It would just add another tool to clean in the end.
If you want perfection out of your paintwork. Then we can talk further. There's nothing wrong with taking shortcuts that don't jeopardize your paint. It's just every now and then, I appreciate spending a couple days going OCD on the car.