can't understand what you want, you already said you wanna go during sakura season, so ... that's the best time to go lor.

or are you asking what is the best date to go? Different places different date, so go refer to japan guide. http://www.japan-guide.com/blog/sakura13/

note that the weather leading up to the season will depend when exactly the season hits. sometimes late sometimes early by few weeks, so if you bought your tickets way in advance then depends on your luck also.

If they ask for your pin, just say you want to sign and they will printout another receipt for you to sign.