So here is what I do with D151, it can be finicky and can dust quite a bit. I don't know how Meguiar's recommends it be used to prevent dusting or overall use, but I've found this works and works good too, well at least for me. Also, D151 has more cut than M205, doesn't do a good job of replacing it though. Kyle was there when I did my experiment at Meguiar's (Well at least I think he was lol)
Wash
Clay (like normal)
tape
I then choose if I'm going to use an orange medium cut pad or a white polishing pad.
I too work at in a 2x2 ft area when using D151.
I prep and apply 3 dots like normal.
So lets say I am using the Rupes 21 with a 6" pad and bp. I do up and down and side to side (so two section passes) at a higher speed and more downward pressure. (In my mind I imagine that I am cutting at this phase. So I imagine that I am using a microfiber pad and a compound) trying to remove as many defects as possible with those 2 passes. (it's always important to watch edges and check for heat build up, pretty much all the time)
So for the 3rd pass in the same section, I slow the speed down to around 3, ease up on the pressure and I start imagining I am polishing.
for the final pass I'll probably still keep it at speed 3 but use polishing pressure. Meaning, very light pressure. Almost finessing the section being worked on.
So overall, I have been happy with 4 section passes. Here's the deal, I am getting paid $xxx amount for a 1 step polish (AIO). If it takes me 3 hours or 6 hours, the amount is still going to be the same. So I am going to do the best 1 step possible, and if it's a regular sized car and I am doing just the paint. I am going to be aiming for 3 hours. (paint only)
I then wipe off the residue and move on to the next section. I go all the way around the car doing it this way.
When doing a 1 step, I am going for shiny, not paint correction. So I'll use my Rupes 21, 6" bp and 6" pad. for the entire car. (I don't switch machines for my 1 steps) Of course each job is a case by case basis, so for the most part.
For the dusting part, this is what I do and have found this approach works best for me, so might for you too.
If I'm doing a section, and I start seeing dust. I'll finish the section. With whatever combo I picked. I then wipe off and before I proceed to the next section. I pick up a brand new pad and prep it, and apply 3 dots and move on. I've found that this way is a good way of battling dust. I've done whole cars with little to no dust at all this way.
If you start seeing dust right away, it can mean you are applying to much product.
After I finish the entire car. I take off the tape and then use D156 for a final wipe. It just brings all your work together and gives a really uniform, finished, glossy look.