The ideas you put forward already work, i forget which country in europe where the Heroin addicts come in the morning to a clinic where a nurse gives them a measured dose off a clean needle, the user goes to inject themselves, waits 15 minutes and then heads off to WORK, can you believe a heroin user can work? ABSOLUTELY if they don't spend half the day looking for a fix and stealing to pay for it, and if the fix is clean and not cut with garbage, the heroin user is very functional, just look into history to find many successful opium or dope users...
Vancouver has needle exchanges, a legal injection site (with medical supervision), and there is also a free-heroin study going on. However, the subset allowed in the study is small, for scientific reasons. (In order to have a statisically valid study, many issues have to be controlled, so there that is why the numbers are limited.) So, far these three items have been shown to work very well. BUT, these issues face incredible opposition.
In Canada, there is, currently, a Tory government (federally), and they have adopted many of the items from the Republican's playbook, so scienctific evidence means squat to them.
(It is strange, because in the mid-1990's, the leader of the most conservative Canadian party thought that cannabis should be legal. In a few short years, the BUSH admin had influenced (infected?) Canadian conservative policy. It is not surprising though, since they hired many of BUSH's advisors to guide their campaigns. And they were elected, although as a minority government, so they will continue with what works. BUT thier election, could have had as much to do with the Liberal party's gargantuan corruption.)
On talk radio (which just goes on to prove the saying "Opinions are like assholes: Everyone has one and they always stink") the uproar over needle exchanges is unbelievable. Some of those talk radio shitheads say "I have diabetes and no one gives me free needles". Yes, but you don't gather with other diabtetics, share their needles, and thereby further spread diabetes, do you?
While opiates in their pure form, and if taken under clinical conditions do not represent a large health issue, they still do represent health problems, so they are not benign substances. Opiates, even at normally sub-lethal levels, can still be lethal. However, this is usually for those people who already have health issues, such as respiratory problems. (That is how opiate overdoses kill; they slow down, and then eventually stop respiration, leading to anoxia. That is why Narcan (a strong CNS stimulant can revive junkies, if administered in time. Narcan does wear off, so those revived junkies should also get medical treatment, otherwise they can die after the Narcan wears off, because the opiates are still in their system.)