My initial thought was that there should be a better way than asking for the value but I see it’s actually a fairly compact way of going about it (and it gets you the dialog for free if users wish to call the script in that way. I’m satisfied with this; it seems to work with all of my scripts which I’ve tested so far. Thanks!
For anyone else who might come across this and wonder, successive calls to rs.Get--- (GetString, GetBoolean, …) appear to take the next space-delimited value in the command string.