Assuming you react as you see it with your stalker sititng at your natural, it can go from the gas in your main to within a couple of hexes of your nexus at your natural before dying. With two overlords (which is no longer unreasonable as you can get them to the protoss main 20% faster) there is absolutely no way to hide anything from zerg going FFE anymore, and they will get one of the overlords out.
I have tested it.
ah k fair enough.
i might add though that i would imagine there wouldn't be many maps where 1 overlord is a guaranteed scout.
2 overlords on the other hand should be able to easily on any map... but considering the costs and having to replace the two overlords i think its a fair trade.
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