Hi,
These presets use "patches" because they are designed to cover larger areas. For the bundled Gravel presets, you'll find two versions for each type. The Large Areas version includes larger patches, ideal for covering extensive surfaces, while the Detail version consists of significantly smaller chunks, which are likely better suited to your scenario. For Mulch presets, if you'd rather not adjust the scale directly, you can reduce the objects' diameter instead. For example, applying a Mesh Select and DeleteMesh modifier allows you to achieve this while maintaining a fully parametric workflow.
I hope that helps.
Best regards