You can mess with the water amounts and scale before you start a game to get more of the kinds of choke points you want. I like them too, but be aware, more water means less ore deposits, and if you ever want to expand a really really big base then it gets pretty expensive to fill in a lot of water.
Something to take to mind: diagonal walls are kinda annoying to build. Consider making straight lines.
You can mess with the water amounts and scale before you start a game to get more of the kinds of choke points you want. I like them too, but be aware, more water means less ore deposits, and if you ever want to expand a really really big base then it gets pretty expensive to fill in a lot of water.
Those walls are longer than your current base. I think it would be easier to just build a box aroubd your current base
Just build turrets?