Choose the start date and how far ahead each sync looks

Today the reach of a sync is set by your plan. We want to let you pick, for each sync, the date it starts from and how far into the future it goes, for example from 1 January and no more than 6 months ahead, within the limits of your plan. The wizard would show the exact window each sync uses. Syncing your entire calendar history, with no limit in either direction, is a later step.