I was playing around with it and have made a fork, applied the outstanding PR to get it in order, and extended it a bit: auto-conversion of record types to dictionaries (once registered), single parameter type constructors (sort of) and a notebook going through the ppx_python examples.
see the readme for details.
the repo now supports registering parameterized types of up to 5 parameters (the limit in ppx_python).
so that’s across the supported type forms: standard variants and records.