I'm almost certain that the new Shocker is like the Impulse and without the eye the rate of fire is limited to about 13bps. Maybe someone else can help?
Personally, i'd recomend seeing if u can save the extra dough for the eye. Even though in theory a HALO can feed 20 odd balls, sods law states that in a snap shot or a bit of accidental bounce you'll get a couple of shots that go too fast and you chop. But well, then again, this wouldnt happen if you're bps was heavily limited....
PS... I'd say, save the money, get an egg instead of a HALO and put the money u would have spent towards the eye.