I think also something to consider is that they are still running cryengine 2... which probably lacks some engine optimisations that most current engines or versions of cryengine have.
Some guy(can't recall the name) said at the instance that you shouldn't need any more than 40 ped ammo..I have also heard people were getting around 20 ish ped from the crate... so id say somewhere between 30-40 ped ammo would probably be safe.
Well..the last section of stage 3 is broken. Has been for over 24hrs now- so anyone still doing it there is no rush...as I highly doubt that the mission will be fixed until monday.:(
I would have left it at the imgur link but i know some people don't like viewing external links, and the nature of the image i felt it important that it was easily accessed hence the change.