I'd say a mix of Low Tech and Midline ships with sufficient Medium Missile/Composite slots, and Kinetic guns, so that the shields can be taken care of. So that would be a few Legions, 5 Pila each, with Gauss Cannons. Then some Dominators, with Mark IX Autocannons and 3 Pila each. If the goal is to spam as many missiles as possible, I'd say Falcons (P) would provide adequate support in that regard, and would have decent survivability as well, thanks to their speed. I don't use Vigilance much, as they are a bit sluggish and delicate to stand on their own and as bigger ships would already bring more missiles I think some Lashers or Wolves should be enough to cover your big ships.
As for destroyers, I don't think there are any particularly good options to be outfitted with Pila. Perhaps Condor, due to the fighter support it also provides, or maybe a beam Shrike?
So I'd use 2 Legions, 2 Dominators, 4-5 Falcons (P), 2-3 Condors, 2-3 Hammerheads, 2-3 Lashers, 1-2 Wolves, 1 Atlas, 1-2 Prometheus. Generally I'd use a lot of ECCM hullmods and fit any ship I can with a Converted Hangar. According to my calculation this would result in more than 32-33 Pilum mounts at least. That would be a decent spam I guess.
Now, I don't know how effective this tactic would be against a fleet which has a few interceptor wings or 1-2 dedicated anti-missile cruisers, but I'd say the above ships would be able to spam the most Pila at any one time.