I'm just wondering for the original poster. Are you doing this as an
experiment? I didn't know of any seedling that will grow successfully in
total dark, or is there something out there?? :-)

No, its not an experiment, its a commercial operation, growing tens of
thousands of avocado trees each year. But this is the first time doing the
etoliation (darkroom growth) on a large scale. That it works, and how it
works is established knowledge. Just sourcing the damn lights seems to be a
problem.