Between "Normal" and "Aggressive" floss aggressiveness options, there is the Custom Floss aggressiveness option. This allows you to customize everything in-between the two and select your own options. Hover over the "?" tooltips to see an explanation of what each setting means.
Remember that there's a "help me decide" link beside the Aggressiveness options that you can click on to help you decide which aggressiveness option is the best for your contacts list.
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