Hey their Frank,
Meguiar's Scratch X is really a very mild abrasive so overall its not really doing much harm to the paint unlike using med - heavy duty compound where your actually removing paint.
When usiing a high speed rotary buffer, the goal is to actually buff till most of the product has dissipated from the surface, and then wipe off the excess with a clean microfiber towel. Of course by hand its all but impossible to achive this as you dont have the speed, heat, or friction generated to buff product in this way. Orbital, or Dual Action Buffers also will not dissipate product in the same manner as a good Rotary will. At any rate you can do an effective job either by hand, DA, or Rotary.
By hand, if your removing swirls, you want to rub the product on in a straight back and forth motion to try to reduce the swirling action. Keep flipping the rag as your product as your product builds up, and after buffing in, wipe off with another clean microfiber towel and proceed to the next step in the Detailing process.
If using an Orbital, or DA, it just takes longer to buff the product. Just keep buffing back and forth in an even motion not staying in one place at any given time until the product starts to dissipate, and then pipe off any excess with a clean microfiber towel.
By Rotary, is the best, and most effective way to remove Swirls, but also requires the most care, and some experience to perform. A Rotary Buffer rotates in one direction at high speeds (recommended no more than 1000 RPM for inexperienced users). The Rotary uses friction, and heat, along with the micro abrasive found in compounds, and swirl removers, and related correcting materials to correct and remove swirls, and other paint defects. The down side is due to the heat caused by friction, it is easy to burn or damage the paint, along with causing potential damage around corners, edges, and around objects like wipers, antenas, and so on.
After you use a mild micro abrasive, its a good idea to follow up with a Glaze like Meguiar's Show Car Glaze which contains oils, and Nuitriants which help further fill in and hide Swirls in the paint by helping reduce the edges of the Swirls which refract the direct light thus making them much less visable to the naked eye. You can also layer Glaze to continue to correct the Swirls if necessary to correct the problem.
And last, but not least, always remember when using a micro abrasive like Scratch X, or related product, you alter and remove any wax, or other form of protection from your paint, and thus you must replace those chemicals again, meaning you must at least put on a fresh coat of wax or paint sealant every time you buff or your paint will fade rapidly! Best case, you should use the micro abrasive every 90 days or so, then glaze, then wax once every 30 - 60 day sto keep your paint perfect virtually forever.
I hope that pretty much answered your question. If you need anything more on this, I am always around.
Go easy, and keep that Black Sheep shining!
Candyman