If you found a reliable seller for the phenobarbital required for DDMAPh, that may be a good place to start.
Although there is always a risk of scams or not legit/cut products,
the best bet is probably from a DNM.
If I could source all of that stuff and not have it be so cost prohibitive it would be a great and peaceful method for sure. And exceedingly reliable, again assuming legitimate pills of everything.
I hope you find everything you are looking for.