I recommend using Wormhole and Crushing Field as a Ghetto hold for when GDF or EMPulse is down it works great. The build really depends on your playstyle, myself I use Lift instead of crush, I know Crush sets up containment but lift gives that bit of Knockdown that gives more control while waiting on Gravity Distortion to recharge. Personally I slot Gravity Distortion with 1Acc/2Hold/2Recharge but I also run Tactics. The build all revolves around your playstyle.