no -- i think it varies between cannons, but the zoom on the quick-reloading anelace is halfway to a sniper rifle, and being that cannons are terrible long-range weapons, i have to assume that the zoom and the slow rotation are just balancing mechanisms. they're a pain to aim at close range. with my cannons bound to a machinegun, i can just get really close to other cannon hounds, watch them thrash around, and hit as often as i can reload. makes hitting fast bastards on wheels and hovercrafts really easy too.
depends on how much stability you've got -- with the backus chip and the heavier sal kar legs, my three-cannon cluster holds together pretty well even when my legs are out. initially i was using a different chip, and with that my cannons would spray like mad when i lost my legs. i think the quick reload of the anelace cannons is worth it -- they reload so quickly that you don't want or need two sets. i'm not sure how much of an advantage two sets is, unless you're using really slow cannons...seems like you have to fire them in rapid alternation to use them effectively, and i get lots of free hits on cannon hounds who predictably fire twice in a row.