Here. If your map is good, it will get noticed. People will talk about it, cc's will know. They'll let 343 know. So just post it here, personal tip though: Don't just release a map out of nowhere, post a WiP thread first. Keep the attention alive of your map, get people involved in the building process of the map. Granted only if your map is actually good. Also get in testinglobbies to get your map out there.
I don't know about where 343 looks (or being a real Forger in any sense) , but I get the feeling that if you get enough testers around here and other Forge hotspots to enjoy your map, it might get out there to the right people. I wonder if 343 checks on the number of bookmarks a map gets.
Make posts in the forum chatbox or try halocustoms. There are also test lobbies throughout the week on here that you can join and make friends with a lot of people.
The Community Cartographers regularly browse through the map databases on just about every Halo website. This includes Forgehub, Halocustoms, many Halo Youtube channels, the Halo reddit, 343industris.org, Halo Waypoint forums, and any other place where people post Halo content. If your map is posted, whether in a database or just as a forum post, it will be seen. Playing in a lobby with a CC, such as The Psycho Duck, Warholic, Nokyard, The Fated Fire, Godly Perfection, Ducain, etc... is also a way to get your map noticed, but if you have posted it then 99% of the time these people have already seen the map, so I would recommend posting. It's still good to play with these people however, as you can get some good feedback on how to improve your map.
I've made a thread for them. ... http://www.forgehub.com/threads/7-griffball-maps-up-for-review.151403/