7 or 14 day pass

Hi, wondering if anyone can help advise what we should buy? Thanks in advance !!

We are coming to Japan, landing at Tokyo Narita on 20th September, staying 1 night in Tokyo and flying from Haneda airport to Sapporo on 21st September.

We will be in Sapporo until 24th September and plan on doing a day trip to Otaru in this time. On 24th September we are flying back to Haneda and then staying in Tokyo until 28th September.

On 28th September we are planning on taking the train to Kyoto, where we will stay until 1st October. We plan on doing a day trip to Hiroshima in this time.

On 1st October we are planning on taking the train to Nara, staying there until 3rd October, then getting the train to Kobe.

We plan on spending 1 night in Kobe then getting the train back to Tokyo on 4th October, and fly home to London from Narita airport on 5th October.

So we are technically in Japan for 16 days and unsure if the 14 day pass is the best way to go, but when we should activate it. Or the 21 day pass? Or if we should get the 7 day pass and activate it when we go to Kyoto on 28th?

Seems like alot of different ways we could do it but don't know what would be best for cost and ease!

Thanks!

Will