I used to have different watermarks for portrait and landscape, color and B&W, with white, grey and other shaded variations. Then I started thinking, "Holy crap, this is getting stupid!!" The idea is to protect your image rights while allowing it to be displayed. So I now have a couple basic ones that work just fine at the bottom left and right, regardless of orientation, that mark them but also be readily cropped out without impacting the image too badly (oh well). And I have a couple that I use for proofs that are more intrusive.
I've realized that anything I post here is to share with the world, get some constructive feeback and maybe make some contacts to sell something if I'm lucky. Like anything on the internet it's bound to get misappropriated and used without my permission. Sucks, but c'est la vie. As I move into any commercial venture it will get more complicated, and I need to decide how best to display work and also protect it. Just like everyone else. LOL In either case, I'm learning that I'd rather just get a mark on there in less time and not worry about how long it takes to put it on. More time for other stuff.