You could apply your own Theme.
I don't really understand this answer. Is it saying that there is a way to set up your own Theme so you never have to resize containers after you've put things into them? In any case, it isn't really very useful to me.
I'm pretty sure the class of problems I'm seeing are because I'm using things wrong, and I was hoping to get some guidance in what to avoid. For example, sometimes a button inside a container will have its text horribly stretched when you change the size of the container using the "scale" tool. If you change the size of the container by hand editing the size values in the transform this doesn't happen. I am convinced I'm doing something outside the expected use of the tools, or there would be a "resize" tool in addition to the "rescale" tool, but I'm new, so not sure how I'm going off the rails.