Look what they're substituted with, when choosing between smoking or ingesting I think ingesting grants a higher bio-availability, therefore more effect. Preferably take them when U haven't eaten otherwise it will take longer for the onset. Smoking may lead to a faster onset and also a more intense but shorter high. But I think smoking Morphine might not be a good idea because it can be a problem if it gets above 85 grad celsius, this will make the effects a bit weaker.