just be sure not to mix opioids of greatly varying receptor affinity as they will compete and it won't be pretty lol...
I'm not too savy with opiates, but I'm assuming by that you mean mixing methadone or suboxone with oxycodone or morphine. (?)
Actually I don't think that is correct. Greatly varying receptor affinity doesn't matter with full agonist opioids (regular opioids). If you take a high-affinity full-agonist opioid, such as heroin or methadone, with a low-affinity full-agonist, such as codeine or hydrocodone, the only problem would be that the high-affinity one could lessen the effects of the low affinity one (and of course the risk of overdose if you take too much in total). It does not cause precipitated withdrawal.
With buprenorphine (Suboxone), it's not solely about buprenorphine's higher affinity for the opioid receptors, but that it is also
a partial agonist/antagonist. Basically, (if I understand correctly): If you've recently taken an opioid and you take buprenorphine, it will kick that opioid off of the opioid receptors and then fill and block these receptors. Since buprenorphine only partially
activates receptors, unlike regular opiates/opioids which fully activate receptors (full agonists), when the receptors are suddenly filled with bupe instead of the opioid they were occupied by minutes before, the result is a sudden and dramatic loss of activation of the receptors, which can cause intense precipitated withdrawal symptoms.
Methadone is a full agonist, so there is no precipitated withdrawal from mixing it with other opioids.
So, full agonists are "regular" opiates/opioids: they bind to the opioid receptors of a cell and trigger a response by that cell, causing the effects we associate with opioids. Where an agonist causes an action, an antagonist blocks the action. Competitive opioid antagonists, such as naloxone and naltrexone, bind to opioid receptors with higher affinity than agonists but do not activate the receptors, so basically they rip any opioids off your receptors, (note that these type of drugs would not be referred to as "opioids" however), reversing the effects of opioids and causing precipitated withdrawal if you have taken opioids recently. Then, there are some opioids which are not pure antagonists because they do produce some weak opioid agonist effects, these are called partial agonists or partial agonist/antagonists: examples include buprenorphine (Suboxone), nalorphine and levallorphan.
I should have been more clear in my original reply above that I was just referring to regular full agonist opioids - the OP only listed full agonists, so I forgot to mention the unique problem of partial agonists like Suboxone.