I love using HammerSpoon for this sort of thing. Not for the faint-hearted to get to a point where you're happy with the configuration, but it's a total Swiss Army knife for scripting just about anything on your system, from window placement/moving to changing DNS or proxy settings when connecting to different networks, to preventing sleep, etc. It pretty much does the job of 15 other tools I might need to install otherwise. Yeah, you need to learn Lua (easy), and be willing to invest a bunch of time in it initially for setup, but once you have done that, you won't want to go back!