How to override drawable resources & layouts for a barrel?

There is a lot of documentation on how to do this effectively for apps. However I have a barrel that will display an image as it is loading up which was designed for the 240x240 pixel screens. When I attempt to use this barrel on a device with a 280x280 pixel screen it is off center and just looks like garbage. It seems like during the building of the barrel I am able to define devices, but it still only generates a single barrel. I figured the resource overriding would have trickled through to the app compiling but it doesn't look like I'm having much joy.

My directory structure for the barrel looks like this:

• /project
  • /resources
    • /drawables
      • drawables.xml
      • splash.png
    • /layouts
      • mainLayout.xml 
  • /resources-round-240x240
    • /drawables
      • splash.png  <--(this is a manually sized version of the same splash in the base resources directory)
    • /layouts
      • mainLayout.xml
  • /resources-round-280x280
    • /drawables
      • splash.png
    • /layouts
      • mainLayout.xml

Running into a small issue with referencing those "splash.png"s with references as well. ALL of the mainLayout.xml's are identical and contain the following:

<layout id="SplashLayout">
    <bitmap id="splashscreen" x="0" y="0" filename="../drawables/splash.png" />
    <label id="splash_text_1" x="center" y="165" font="Gfx.FONT_SMALL" text="@myGarminAPI.Strings.splashMsg_1" color="Graphics.COLOR_WHITE" justification="Graphics.TEXT_JUSTIFY_CENTER" />
    <label id="splash_text_2" x="center" y="190" font="Gfx.FONT_SMALL" text="@myGarminAPI.Strings.splashMsg_2" color="Graphics.COLOR_WHITE" justification="Graphics.TEXT_JUSTIFY_CENTER" />
</layout>