You are doing it wrong. I don't mean to be contrarian but if you want to be successful as a independent developer (I have been for almost 15 years now) and you are looking for a CRM you are off the rails. CRM systems are for the most part, for companies or sales individuals who need help managing the number of contacts they have at any given time and ensuring they follow a structured interaction pattern. I know about…
The only thing I have at a "large number" level is a very stupid web application storing just 2 things: an email address and a corresponding full address like you print on the envelope. Then every year, I can send 125+ new year cards. I take the time to include a nice design for the card, people enjoy them and this is a nice way to keep in contact with a large number of people.