The difference in the file size is not really an issue. The generated file size can be smaller or much bigger depending on how many custom workitem definitions are found in your guvnor repository in the package you create your process in. In case you do not have any workitem definitions, the file size of the created json is actually smaller as the .orig ..this is fine.
As far as log levels, check out this post with one answer -> http://community.jboss.org/thread/150803.
Hope this helps.