Buying Japan Rail Passes

Hi! We will be in Japan for 34 days and would like to purchase a 21 day and 7 day pass for each of us to cover most of the trip.

When we place this order, should be be using the same start date (they ask for this on the order form) for all passes as the day we arrive in tokyo, and then when we activate the passes use a different activation date for the 21 day pass from the 7 day pass. As in activation for the 21 day pass is for example Nov 1 and the activation for the 7 day pass is Nov 22.

Just struggling with the best way to approach this.
thank you.