After writing script's for a few years now I feel like I still don't have my head around the correct way to build UIs. While building a simple palette with a few buttons is relatively straightforward, I am more curious about better resizing, dynamic layouts, etc. For instance, having something go from a row layout to a column layout when the window is sized below a certain width, or buttons flowing to a second row when the window is too small to view them all in a single row, or even things as simple as dynamically centering buttons.
I have been through Peter Kahrel's Script UI for Dummies and that has given me a pretty good idea of the functionality of windows, but I still feel a little out of my depths when it comes to layout. Similarly this extend script training does a good job at talking about functionality, but seems a little short on info about layout.
So, for all your scriptUI pros out there, what are some good resources for learning how to make not only functional panels, but panels that look nice and work nicely in different sizes?