Torque, no you wouldn't need to set an altitude if they used the same VT fused rounds. They did in real life.
VT fused Flack rounds have a small, cheapo radar inside them that radiates out to the side, about a 50 foot detection range. Whenever it passes an object, it triggers the detonator.
The Army Anti-aircraft artillery batteries used them too in their 90mm flack guns.
Hans.