For what it's worth, the Build.PL also threw me for a loop, thinking at first that you were calling dzil as part of the module installation phase. Maybe a script to generate a script to help you run dzil is overkill? I think you should just use whatever cpanm and dzil are found in the path.

I have never actually used dzil install. I always run dzil build and then run cpanm manually on the .tar.gz afterward. Does that work in your case?