BTW, in a related matter, the scenery.cfg hierarchal examples in your guide show the default listing/placement of Title=Terrain, which is a universally critical piece of the default scenery ladder, in a #2 spot lower than Default Scenery. As you know, this entry is the listing for the all-important Scenedb\world\scenery folder, which also happens to be the placement folder for Rhumba's watermask files, per your instructions.
According to the sim's scenery convention, the Terrain entry is "locked" in the highest default position and cannot be swapped with the Default Scenery entry into your recommended positions using the sim's Settings> Scenery Library dialog. The sim will not allow this entry to be moved at all. The user will have to swap these two manually by editing the scenery.cfg outside of the sim. I can't determine if this was an oversight typo or an intentional reformat in your guide, but if this "swapping" is an important piece, you might want to update the guide to mention this for the users following you. Just thought i'd mention it for the benefit of others who might have noticed this.
[Area.001]
Title=Terrain
Local=Scenedb\world
Active=TRUE
Texture_ID=1
Layer=1
Required=TRUE
Remote=
Regardless, it makes no difference in my 'situation'. Still looking for an answer...