Hey! It's not perfect, but here's the bitmask I'm using for this tileset! I use 3x3 (minimal), and an atlas for the un-bitmasked-sections. The autotile can't discern a block-wall-with-grass-on-all-sides from regular grass, since both would have tiles in all directions, so the autotiled version is comparatively simpler, and I use it as a base before painting the finer details myself (if you use an atlas, it doesn't update the autotile, so it works great).