I'm assuming you mean something like :modal/arg1, :modal/arg2, ... along with a :modal/numArgs? I can see how you'd reconstruct the arglist, though I'm not sure what :db/type you'd make the args in this case. (FYI I ended up just serializing the :arguments to a Transit string. Some perf loss but acceptable for my use case.)

Say n is some member of the vector, have facts like [n :vector/member-of somenameoridforvector] and [n :vector/index somenumber]

And then you can have whatever other facts you want to store the actual value whatever that is

This is classic data normalization from SQL databases https://stackoverflow.com/questions/3070384/how-to-store-a-list-in-a-column-of-a-database-table