Thanks! (and sorry for not approving the post sooner, I missed it :<)
As for the feature request, in the long term, the plan is to provide a proper map editor so that people don't need to fiddle with limitations of guidance maps. I'm not sure when I'll work on it, but having much tighter control over the results is something I'm definitely interested in. I'd like Gleba to eventually have a "main world" for the game part of the project and I'd like to handcraft it with the help of Gleba's generative tools so it's in my best interest to give more options to control things like coastlines and mountains.