Decoratives to the north and west will overflow onto tile patches;
Could this look 1 (or maybe .5) tiles to the north and west as well?
It is possible to work around by tiling that one extra tile and then removing it, but that's a pain to do in general.

Unfortunately not, sorry. All this mod actually does is change the % chance a tile has to remove decoratives to 100% (base game has 15% for brick and 25% for all concretes). I don't want to introduce the extra complexity and potential performance hit of scripting, and I don't have time at the moment anyhow. If you want to try adding it yourself as a toggle-able option I'd be happy to integrate it though.