Yes, we continue work on designer, and I made screenshot from new version. It will change at least one more time before publishing new version.
Default form size is option for Designer, not for source. When you resize form in Designer, it saves size, so when you will open same source next time, you will see your form with same size as you make it last time. When you open some form in Designer first time, it will use default size from preferences.
If you want to set size for SWT applications, just call shell.setSize() with needed arguments.