I'm not sure of a formalized greeting thread in the "upper" forums, but there is
this thread in the general DF forum.
You can probably also visit the
General Discussion forum in the "lower" forums, where there are much less restrictions about what topics belong where.
Ultimately, though, if you just want to casually talk about DF, then
Gameplay Questions (for help in playing the game),
DF Fortress Mode, or
DF Adventure Mode.
Also, there isn't much need to apologize - just about everyone comes to either the suggestions or the modding forum first off. I pretty much just have a form response at this point for people making their first suggestions.
When talking about your suggestions in the future, though, I do recommend you take the time to actually plot out the effects of the changes, rather than ask "how many jobs they would need" - it makes a more persuasive argument when you show your work, and reveal research you have conducted, and quote and respond to other, similar arguments in the past to show that you have addressed those old concerns.
A suggestion isn't just a casual conversation, it's an argument for a change. You need to arm yourself with the arguments that will persuade others to your point of view before you launch a suggestion thread.
Good luck in your future endeavors.