Download BFGminer 4.4.0. (https://bitcointalk.org/index.php?topic=626361.0) My batch file looks like this:

bfgminer.exe --scrypt -o POOL:PORT -u USERNAME -p PASSWORD -d gridseed -S gridseed:\\.\COM11 -S gridseed:\\.\COM13 -S gridseed:\\.\COM14 --set-device gridseed@\\.\COM14:clock=838 --set-device gridseed@\\.\COM13:clock=863 --set-device gridseed@\\.\COM11:clock=875

You can open the Device Manager and find the COM ports of your gridseeds.  Use the drivers installed with Gridseed.  DO NOT use Zadig.  That is only for CGMiner.  Just set the clock speeds and find out which have many hardware errors.  If you run for 1/2 an hour and none have HW, bump the speeds up a little bit and try again until you start to get them.  Then drop the frequency just a little.  Frequencies that work are:

800, 813, 825, 838, 850, 863, 875, 888, 900

If you need help, I'm on twitter @bradleyploof