The option of using Any Starting Era is definitely makes this Gauntlet winnable by nearly any competent Player at perhaps Monarch level or above. Just select Modern (see GM-21 for strategy) or Future (No Tech Race at all and its easy to beat the AI in military production and Win. Neither option will likely produce a top three finish though. This will be Fun, especially for those with little or no experience at Deity or any of the higher (Monarch+) difficulty levels.
I suspect that Ancient Era will capture the top three spots, but only if significant advantage is gained by the Classical Era, thus beating out all successive Eras (assuming proof by induction is valid here). Yes, even at Quick Speed this is quite possible. One just needs to maintain a Lead in Military Technologies to make "starting in the Ancient Era" an early advantage.
The wild card in my opinion when choosing a Starting Era is the number of Settlers one starts with, the Starting Population and pre-built Buildings for a given Era. Also, I'm not sure what advantage the AI has at Eras after Ancient. So, I'm just hedging my bet on Ancient Era here. The Classical Era may have a good chance at Winning
However, its possible for an Ancient start to win this Gauntlet before some of the later Eras even begin.
It's also important to point out that many later Eras may have a much later Starting Date in BtS than in Vanilla/Warlords, but I suspect that this is most significant for Marathon Speed and may not be a significant factor at Quick Speed.
This is the most underutilized option for Conquest. It opens many possibilities for Conquest that just don't exist at Epic or Marathon speed. We're talking Fun, with a Capital F. A vast array of unique units can be Utilized. Just beeline the unlocking Technology and spam the units.
Since its Conquest, just raze Cities to avoid an Economic Crash without hardly a penalty.
At Quick Speed, there are many more opportunities for different paths of Technologies (mostly Military). Conversely, shutting off research and spamming sufficiently advanced units in vast numbers will overwhelm the AI, especially in the Ancient Era.
Buyer beware: I don't have much experience playing Conquest (or Domination) at Quick Speed, so use the above at your own risk. Just having Fun with this Gauntlet will be a major risk mitigater.
Don't forget to select Vassals for a quicker Conquest Win, but only if you plan to complete Feudalism which unlocks this option for the Player. Vanilla Players can have a good cry now (Vanilla doesn't have Vassals).
Did I say this Gauntlet will be Fun? No, well, this Gauntlet will be Fun!
There will be plenty to learn too.
Sun Tzu Wu
(large score) Oh well, it shoulda gona down a year ago. 
. You need more troops than on any other level and you have less time to use them. If you can overcome these things, however, it's pretty impressive.
