Are you using the Designer or Code to size your layout(s)? If Designer, you can use Autoscale all, in the Tab to scale everything correctly.
If code it's a little harder.. For text size DIP does not apply, so just straight numbers. I usually set a fontsize variable and then adjust accordingly between small, large and extra large devices. Coding only.
Erel has a tutorial about this...
http://www.b4x.com/android/forum/threads/supporting-multiple-screens-tips-and-best-practices.17647/
I think in your case you could also define the screen as 360x640 pixel density 1, which covers those devices of that actual screen layout and density and your device which is effectively double that.