I just did something very similar. To stretch the app without creating new layouts I used dimensions set in XML
res/values/dimensions.xml
res/values-sw600dp/dimensions.xml -> 7+ inches
res/values-sw720dp/dimensions.xml -> 10+ inches
Dimensions are resources files:
<dimen name="default_padding">11dp</dimen>
You can increase the dimensions by about 30% in the 600 and 720 file.
Then simply used @dimen/default_padding
in your layout and it will be scaled
Regarding images, either you make sure you have all your assets in all densities, or you set fixed size to you ImageView
‘s and appropriate scaleType