Yeah, neither of those options is what I want.
Auto Scaling sets the window size to match the host size. I want it the other way around.
Scaling with the ratio hard codes a size which also isn't what I want.
I've tried both of those options but neither one checks the bot under settings called "Scale To Window".
It seems that if I set it and then save the config, it's actually the option called Directx in the .vnc file.
But I was able to get it to work that way so I'm good for now.