I don't know. If I just go with the simple "Rail + something" or "Auto + something" routine, it's just like any other map. Give a good player a rail, and easier domination is eminent. Same with Auto. Giving the players freedom to choose what combination they want to use is what I think something that would go well for players that haven't been able to experience the other combos. This would allow for players to find their own way to win with their own combination, and the best part is that you don't have to stay with the same combination the entire round, which allows for creativity on the entire skill curve. So even if you aren't that great at the game, you can still have fun mixing different rings defending your base.
Oh and, no, it's not going to be "lol homing auto rail". The map is fairly big enough to spread each type of special ring to different parts of the map without THOSE kinds of combos being allowed. And even if the respawn time is low, I've created a makeshift way to prevent this from happening.
Still, I'm not sure if it's such a good idea because the better players will GO for the homing rail, or the explosion rail, just because of the benefit of not having to aim exactly at your target, though it takes more time to recoil...