Have you ever considered allowing a virtual signal (perhaps certain groups/subgroups like simple virtuals and the 'planets' signals) to be used as the trigger, and match the name of a platform if the first character is that signal? IE if I have a platform with a 'X' virtual signal, sending that 'X' signal with any value to the silo would try to launch the rocket to a ship with that as the start of the name?

That is to say, the names are things like:
[virtual-signal=signal-X]Canterbury
[planet=vulcanus]Canterbury
[space-location=vulcanus]Canterbury

The reason I bring it up is the mod No Space Platforms generates a bunch of dummy platforms that use things like [space-location=<target planet here>]PlanetName as the name. I'm not certain why No Space Platforms uses space-location, whereas if a person manually adds a planet icon to a platform name it uses [planet=vulcanus].
https://mods.factorio.com/mod/Space-Age-Without-Platforms
https://github.com/danielmartin0/factorio-No-Space-Platforms/blob/main/scripts/Platforms.lua#L6

I would never ask someone to spend the effort to integrate with a single mod like that when I'm probably the only person on earth who would use that combo, but if it were more generic of putting the silo into a mode where any virtual or planet type signal fed to the silo would attempt to match with the first platform with that icon as the first character, that could be a friendly way to do the matching up instead of the numeric system you have right now. Maybe something to consider?

Either way, this mod is great and I'm sure I'll be using it in one form or another for my Space Age nano factory.

I should add, this mod works fine with No Space Platforms if you do one of these:
A) The Auto mode works totally normally attempting to match up to requests.
B) You can manually set a silo to launch to a specific platform every time using this mod's UI, and have one silo per platform (in case of No Space Platforms, that's one silo per destination planet)

So it's only in the case where you want to specifically launch from a single silo to specific planets without using requests that it doesn't work, because you can't change the name of the virtual platforms that the mod creates.

I ended up doing something completely different, but it should work for you: there is now a "multi-signal" mode that lets you set up to 8 launch signals, each with its own target. It takes a little more setting up by hand, but you can of course copy-paste the settings once you have it the way you like it.

Awesome! That sounds like it'll work just fine. Thanks much.