Yes, Line of Sight Visualization was completely integrated into the toolkit in one of the updates. However, since the toolkit has actual AI, the vision parameters are customized through its AI Perception component as shown here:
You can find more details about customizing the AI Perception settings here: https://unrealpossibilities.blogspot.com/2017/06/top-down-stealth-toolkit-basics-ai.html
Just make sure that you are editing these values within the blueprint editor and not from the level editor. Last I checked, components in Unreal have this limitation where even if we expose these values to the editor for easy customization, they don’t reflect the changes until the game starts.