What’s your Postfix version? B/c since 2.3 smtp_use_tls is obsolete. smtp_tls_security_level is all you need.
And why are you setting certificates for your CLIENT? Please, do read the documentation.
More over, I’m hoping you didn’t replace your smtpd directives, but added the smtp ones? Because now noone can reach your Postfix SERVER though TLS…
And about blogs… Yeah, euh, there’s a lot of bullcrp out there I’m afraid… All well-meant, but bullcrp nonetheless.