@Marv - aufs libs are in /usr/lib for the ubuntu version - (particularly) earlier ubuntu derivatives expected to find it there, with /usr/lib64 being a symlink to /usr/lib. Are in /usr/lib64 for slacko version as those derivatives would expect. Not following these conventions can give unexpected results, & I didn't want to add any potential point of failure. (32bit & overlayfs-only kernels don't need the differentiation).
Note that rapid progress in woof-ce, producing kernels as github artefacts, combined with increasing inter-operability of other-distro kernels, & the fact that many users of old puppies simply stick to their original kernel, makes it likely that my kernel methods will become redundant sometime this year.