You will need to decide which sensi mode you are going to want to be using, after decided change to 1,2,3 or 4 (details in manual), with a full stack of balls and hopper turn the gun on with sensi on and take up to 10 SLOW shots to calibrate the sensi, after this you can fire as fast as u like, the halo has the possibility of breaking the sensi crystal as the rod is hammered by the force feed of the halo and this in turn can fook the crystal, with sensi off and a halo on it it is unlikely you would chop, with my speed i left sensi off and when using a slower hopper with sensi on i found it was broken from the halo but i didnt realise as i obviously hadnt need the sensi when using the sensi, it is not a break beam eye so you still have the chance of chopping, the sensi just reduces the risk.
Cheers
Liam