Hi @hughperkins,
If you are interested in inducing sparsity, you might want to checkout this project 146 from Intel AI Labs.  The documentation 54 tries to shed some light on recent research related to sparsity inducing methods.
The project includes a stand-alone Jupyter notebook that attempts to show how L1 regularization 231 can be used to induce sparsity (by “stand-alone” I mean that the notebook does not import any code from Distiller, so you can just try it out).
Cheers,
Neta