I took Yelgis' advice and am running 54% CDR for full stun lock on the RG's and it is pretty much fool proof on all of them except that one poison/octopus looking thing that flee's backwards upon spawning. Once you get to him it's game over like the rest. When I wasn't farming, the main issue I had was killing the RG in time without multiple deaths and this effectively cures that. Once I get back to pushing 50's I think this will be a huge help. That being said I am a huge fan of fighting everything before the RG at max range and I probably wont change that since it seems to be the most effective.

Currently I'm running an Explosive Blast build and farming 35-40 GR's in under 4 minutes. Somehow 12 Woh's have dropped since the Era began and 5 of them have been ancient (I know right?!?!) so I'm putting them to use. It's pretty crazy how fast you can fill up on Legs with the kill speed Wizards have.