>What is the best way to get the value of a form.WindowType before the form or a class is instantiated.

How about surfing the _screen object?
lnwindowtype=_screen.WindowType

While discussing _screen let me recommend it's use for other things. I use it to store user information by adding properties when someone logs into one of my applications. It is also a very quick way to get that data as in _screen.user where I have previously created that property and populated it.