I am not even sure how well it will work with a buffer, I believe it is more of a hand polish.
Remember though that either way you go about it, it is only a very light polish and won't really remove heavy or deep swirl marks
It will remove much of the hazeness from the paint though.
Here are some pics of the Neon I did the other day..
In this picture, you can clearly see the difference in swirls, but, there are still MANY swirl marks that the Scratch X won't touch.
Here you can see a better represantation of just what it will and will not do. at about the middle of the pic you can see the line of where I worked the Scratch X and where I stopped. You can see that much of the haze is gone and it does give a better reflection, BUT, many swirlmarks will still remain.
I did the entire car by hand with the Scratch X and honestly was very impressed with the results. I do not have a buffer yet, so Scratch X is the best I can do at the moment.
If you use it by hand, I usually use about a dime to nickle sized amount on my pad and rub it in very firmly in an area about one square foot. depending on temperature / humidity / sun or shade you can do more or less at a time, but that will take some expirementing.
Good luck, and take some before, during, and after pics