fwiw, the "imagebuilder" seems best suited to what you need to do.
After doing what you suggest i got the following warning after making those command :
- git fetch --tags
- git checkout v19.07.1
- ./scripts/feeds update -a
- ./scripts/feeds install-a
- make clean
- make menuconfig
- make download
- make -j 2 Files=files/
those warning shown after running these command 5,6,7,8