As you own the official blu ray set of the Original Trilogy you are eligible to acquire Harmy’s Despecialized Editions.
The custom blu ray set you are after can be found here:-
NJVC Custom Blu-ray Set of Harmy’s Despecialized Editions now available on Mega
in the ‘Star Wars Preservation’ forum.
solkap has provided a step-by-step guide on how to acquire this particular set.
If you have any issues then that will likely the most suited thread to ask any questions in - MTFBY 😃