"1000000:1 ratio would be pretty good considering that is working to not working"
Actually, it wasn't specified which side working and not working is on. Though it was implied
"500kb script...that is insanely big. I doubt it would be that long."
A typical Hybrid script is easily over 100kb. The initial setup of a slayer task completer could easily be half that size, given the complexity of records / data that would need to be stored for AT LEAST 2 slayer task givers (burthrope and _).
500KB is a very realistic number given the nature of the script.