Playing around with torpedoes again. Got this one one a small grid and doesn't look too ugly even with the connector on top. I learned that Timer Blocks are extremely useful for setting up multiple actions to performed with a single command. Timer Blocks also have a "Trigger Now" function. With them, I can toggle the thruster, unlock the landing gear arm the warheads, set a separate timer to blow the warheads after a while in case it misses, and arm the impact sensor.
Not sure if the test fire detonated them all simultaneously, since the sensor sets a 2-second timer on all the warheads at once. I think one triggered on impact(vaporizing the rest), but the hole left in the test target was centered around the center of the torpedo - 8 warheads are arranged in a ring around and behind the impact head(a blast door edge pointing forwards) with some light armor plates in front of them. Left a nice hole cutting entirely through a layer of heavy armor and a layer of light armor behind it, big enough to fly through - the same armor that battleship cannons and planetary impacts had trouble with.
The next trick to it is getting it to fire semi-remotely(from the controls of the launching ship, anyhow). I finagled a bit with RC blocks, but they're awkward to use and require an antenna(which makes everyone see it) or laser antenna(too big, haven't figured them out). I'm thinking of, while the torpedo is connected to its fuel line, to set up some Timer Blocks to give it a second or so disconnect the line then launch.