Well, the general rule of thumb is if it's open bolt (e.g. Timmy/Angel) stay away from the Halo. I hae yet to use an Angel/Halo combination (whether it be Speed or IR3) that didn't give regular breech bursts (2-5 balls per hopper full)
As cockers are closed bolt, they should theoretically work well with the Halo.
However, as ever there is an exception that proves the rule - Viking is open bolt and when I had a go of Colliers it was phenomenally quick using a halo and not a single burst after 1 hopper and 2 x 140 pots through it...