SweetFX has several SMAA 'presets' you can use; Low, Medium, High and Ultra.

The numbers for the Ultra preset are -

#define SMAA_THRESHOLD 0.05
#define SMAA_MAX_SEARCH_STEPS 32
#define SMAA_MAX_SEARCH_STEPS_DIAG 16
#define SMAA_CORNER_ROUNDING 25

The numbers for the Low preset are -

#define SMAA_THRESHOLD 0.15
#define SMAA_MAX_SEARCH_STEPS 4
#define SMAA_MAX_SEARCH_STEPS_DIAG 0
#define SMAA_CORNER_ROUNDING 100