I played with this a little bit...
Though I found that putting them on a logic clock was not so useful for ships you want to fly, since to get the number of missles you want.. you need a substancial level of power, which makes it essentially your primary weapons system... and for that it's practically useless.
It did give me an idea though for an interesting zone defense weapon...
A ship with no thrust, just power, and swarm missiles on a logic clock (as you're mentioning in OP). It would instantly kill you once you get out of it, since heat seek missiles DGAF like that, but that's half the fun.. Because this little doodad will attack ANYTHING that comes near it.
One thing to keep in mind is that if you want a large number of missiles, you'll want to place single missile tube blocks which aren't touching.. each one with 100% mod from secondary effect will get you 10 missiles. I didn't get to test it much, but I was told that adding more than necessary of the secondary block will not increase it's effect but will increase damage? Would be a nice way to get the damage of each swarm up, without having to place 2 blocks per swarm or 3, 4, ...,
[DOUBLEPOST=1438120616,1438120489][/DOUBLEPOST]Second note: I did make use of them once I experimented a bit. I use a ship which has a Missile+Pulse weapon (heavy bomb). That bomb is slow, so it has a high probability of getting shot down by anti-missile systems.. SO.... I added in a couple hundred swarm missile pods.. I fire those off, then the bomb goes through the middle of them. Sends anti-missile bobby-ai turrets into a seizure.