This might just be a typo or maybe you're not speaking in literal terms. "Adderall" is a distinct substance from Methamphetamine. Adderall is a mixed-ratio of un-methylated Amphetamine salts.
I'm just gonna say, anyone who values their drug supply and wishes to use it efficiently should forget about "smoking" or "vaporizing" these tablets as a route of administration. You have every other ROA available to you. In the best of circumstances, with "great" technique in vaporizing, you're no doubt going to destroy a lot of active substance through combustion.
In Southeast Asia they have these tablets called Yaa-Baa. They are Methamphetamine tablets and they are most commonly ingested through vaporizing off of foil. Among other additives, Caffeine is an essential component for making the tablets vaporize properly. On more than one occasion I listend to someone complaining that the tablets were "wrong" and wouldn't vaporize.
That should put things in perspective.