I am totally sold on the idea of this mod and I think maintaining launch silos and payloads and using them to strike much longer than artillery can is a very cool concept. I like the graphics and how it performs. However:
-Modular payload types are almost completely undocumented. Your title cards show the effects they have but not relative strength. It doesn't provide enough information as to how I could possibly shape my payloads without jamming random things into it and seeing what happens.
-Some modded ammunitions don't seem to work. I tried uranium sniper ammo I had laying around from Schall's mods and there was no effect on landing.
-Blast radius is incredibly small without using nukes right off the bat or packing 2/3rds of the payload with explosives. This leaves very little room to experiment with the remaining one slot.
-Being limited to capsules/handheld ammunition in a random spray tends to make these very weak individually against significantly sized or massed biters. I think the missile itself needs a built-in explosive payload that will at least blow up whatever it directly hits. It feels like a complete waste to use anything except nukes.

Thanks for your reply.
Since the payload is completely modular and (as far as possible) compatible with mods there is no way to document it.
I could only describe it as that: The missile will shoot any ammo type like the corresponding weapon would.

Sometimes this does not work because a special behavior was implemented (Like Laser Ammo Types).
In these cases I can't do anything about it. That would require adding all those ammo types by hand and script their effect on my own which would take weeks.

I decided against a built-in explosive because there could be some beneficial ammo types (repair capsules for example) that you would intentionally fire on your own base.