@Royal Scribe The HW overland style is included with the core app these days.

I made an "Effluent Scum" fill you can use in various different scenarios?

I think Herwin gradually moved on to photography more than fantasy art over the years, so while it would be nice to see these styles expanded I think it's probably not that likely to happen.

If you can't get rid of the layer is it really worth scrapping everything to start all over again?

Layers aren't anywhere near as important as sheets. Most of the time I completely ignore them.

Sometimes they are included in the main catalogue, and others they have their own catalogues. Try clicking the buttons on the lower of the two button bars above the window and see what you have.

It depends on the style.