How I would do it:
1. Snow foam the car to loosen dirt
2. Rinse
3. Wash car with 2BM method. Have one bucket as just water with a grit guard. Have 2 washmitts, one for top part of car, one for bottom part. Rub wash mit against grit guard in one bucket, then rinse in the next.
4. Rinse again
5. Dry with a big drying towel. Place it on the paint and dab it. Remove (dont drag!) and place on the next bit of body, dab and remove. Repeat all over the car. Dont use a flexiblade or wipe the car dry
Job done with minimal swirls