Hey to the OP, if you´re referring to vaporizing Methadone tablets on foil, then I have to admit that I have no idea. I know people have vaporized other pills like Oxycodone. I´ve never heard of such a thing and you´d be a bit of a pioneer. If you´re looking for a faster onset, rectal administration hits Tmax at 1.5 hours vs 3 hours on average, so, twice as quickly essentially. The duration is not significantly effected either. If you have Methadone liquid, it´s ready to administer, tablets, just mix with water.
@Jnowhere you need to learn how to perform a Cold Water Extraction. You also need to learn about Volumetric Dosing. These are the two keys to answering your specific problems. A CWE removes easily all of the Acetaminophen from your tablets. Volumetric dosing will allow you to make extremely minute decreases in your dosage using the solution you´ve prepared from your CWE.
I´m going to be back on in a little bit. You can message me or we can discuss here.