Terebine is not an equivalent substitute for JD.
The source indicated above somewhere, states that it contains:
INGREDIENTS
Mineral turpentine 72%
Cobalt octoate 14%
Manganese octoate 14%
The JD used stateside in battling OI and II gaaks contains only:
Petroleum Distillate
Naphthenic Salts
Accept only the real mccoy!
I'll look around an aussie search engine to see if JD is available at the consumer level.
The PCE will work to remove most polymers.
Since these are time released and most likely dry matrix, try doing an IDEA extract as outlined, followed by an A/B.
This should get ya closer than you are now.
The IDEA method was never performed on sulfate pills to the best of my knowledge and maybe somebee will offer some refining suggestions or warnings if this route is chosen.
There should be no side rxns with the sulfate using Acetone, Metho, Isopropyl, aqnd PCE as the wash mix.
In fact, if what was posted is true about the Pfed sulfates alcohol solubility issues, The IDEA Method might be better suited for sulfate compared to hcl pills.
If this seems like a worthy try, The write-up can be referenced here:
https://www.thevespiary.org/rhodium/Rhodium/chemistry/pseudo.xtract.smackdown.html
TCE and PCE are the same chemical!
Good luck!