we've removed formal support for our Webkit engine on Android since RhoMobile Suite v4.0, so I'm not really surprised that it may have some issue.
My suggestion is to switch to the native browser on Android. You can have some issue with the default configuration of our rendering engine because, with no viewport configuration, it usually render the pages a bit smaller than other mobile browser:
Regarding how to include your own Config.xml in a build, you can use the build.yml option:
Copying your Config.xml in your project (for example in a new Config folder) and the add a reference to it in the build.yml:
I'll have a play today with the native Android browser using the viewport configurations.