My best attempt at creating a small (miniature) Worm Gear using Inventor 2018 Design Accelerator produced this

Here the Gear is about 100 mm diameter and I need something smaller - about 60 mm diameter. Logic demands this must be possible - not everything needs to be scaled for shipbuilding - yet I cannot find tutorial, video, PDF documentation or other educational material to assist me.
Can some kind soul please point me to a textbook or substantial video on using Inventor's Design Accelerator for such a task?