Long-term visas (Madrid)

Greetings --

My wife and I are in the process of applying for long-term Spanish visas. We're from the U.S. Has anyone here had recent experience in this process that you are willing to share?

Also -- the visas we'll apply for require, "An original medical certificate printed on a doctor’s letterhead, verifying that you are free from yellow fever, cholera, and the plague, and free from drug addictions, and mental illness." Has anyone applied for such a certificate? Can you recommend a doctor in Madrid who provides such certificates?

Finally -- is it reasonable to go through this process on our own, or should we hire a local attorney or expediter to help in this process?

Thank you.