This does not directly address the question, but it is topical.
I do the same thing with my domain and it was always a hassle to make sure I filled in the correct From: address on each email I sent. Then I found the Virtual Identity Plugin for thunderbird.
It automagically remembers what From: address to use with what To: address. It also makes the From: line fully editable on the fly and remembers what you used for the next time. It makes it dead simple to make sure that you never accidentally leak one of your unique addresses to the wrong person/company.