Congrats on 1 year on HRT!
You have some good choices when it comes to surgeons in the Seattle area.
I'm not familiar with Dr. Miranda's letter requirements. Typically, it's just one letter for Top Surgery. You could call her office to find out specific requirements: 206-215-6221.
You can also check out these resources for guidance:
1) Surgery Sample Letter
https://transline.zendesk.com/hc/en-us/a...ple-Letter
2) FTM Top Surgery Requirements and Eligibility
http://topsurgerymidwest.com/ftm-top-sur...uirements/
3) Top Surgery Requirements FTM & Non-Binary
https://universitygenderaffirmationsurge...quirements
I hope this helps!