>>>The Resize class doesn't resize the form itself
>
>This, you will need to do yourself. I suggest doing this in the Init(). If there is too much screen flicker - you may want to toggle the visible or lockscreen settings.

Init() event is safe from flicker (it can happen in Activate event only). I guess that 640x400 situation must be handled with setting Form.WindowState=2 and then explicit call Form.Resize(). Resize event should contain layout handling code for form controls.