Defining a swirl or scratch is very very subjective. Many people here call micro marring "swirls" and other's with very deep scratches a swirl as well.
Do to that fact, it's impossible to give an easy answer.
The general notion that we go by is:
Use the least abrasive product needed to remove the defect.
With experience, you'll get a feeling for which works best for which defect but until then:
Also, do you intend on removing the swirl with a polisher or by hand?
Start with a Swirl Mark Remover and polishing pad. If that does the trick, then next time, try a paint cleaner (SEC GEPC Vanilla Moose). If that doesn't cut it, try a cutting pad. If that doesn't work, then either try a wool pad or move up to a fine cut cleaner with a polishing pad. If that doesn't work, try a FC with a cutting pad.
No go, then you have a scratch and probably not a swirl.
Move up to a Medium Cut compound and cutting pad. Then a Swirl Mark Remover polishing pad. Complete it with a hand application of a paint cleaner. Then the topping of your choice.
Paco