Where to post this message
And yes, the wiki is not really the place for this, but I can turn it into an FAQ later so no harm done.
The appropriate place is the mailman-users list as you mention:
You can post while still a non-member, but you have to wait for one of the admins to approve your post, which can take a little while, so subscribing yourself first is definitely the best option.
PS - you did answer the confirmation request, right? I know mail can be slow, but I haven't seen it take 8hrs to subscribe before...