Personally I feel about 500-600mg extracted from OTC tablets with reasonably good techique is about the maximum best effects you get from codeine, I feel for me personally whatever dose is left after you account for losses is around my ceiling dose so to speak (probably works out around the general consensus of 400mg or so). There are more metabolites of codeine than just morphine and codeine itself is somewhat active, I have dosed up to a gram or so and while the effects are increased, I find it less enjoyable because there is an increase in the amount of what I find to be more stimulating opiates but the morphine dose doesn't increase beyong the ceiling. I also find that whilst higher doses get you higher, per mg you get alot less return, for example 800mg is nowhere near double the high of 400mg.
Unless you are tolerant you will likely get very sick and a strong histamine release from high doses, especially without antihistamines, it is also a much more stimulating high in my experience and personally I like to take opiates to relax and ideally nod (although this is rare with codeine these days even with the addition of numerous potentiatiors).
Lately after some decent tolerance breaks I have found myself being able to get good effects for several days in a row without exceeding the ceiling, in the past I had an attitude where increasing the dose would make the high better and between that and use of harder opiates ended up with a tolerance where codeine did basically fuck all on its own but make me itch. I really think that while you can get stronger effects beyond ceiling doses unless you are an extensive metaboliser or want a speedier high and can handle the side effects it is pointless, and dosing this high also makes codeine a much less viable drug to get decent effects from with any regularity.
People seem to report more stimulating effects from lower doses but I never got this, codeine never did much beyond mild relaxation untill I started dosing above 300mg and unless I exceeded the ceiling it has always been a sedating buzz to me, although if I choose to I can function like I am pretty much straight I consider it a waste of the high, I really have to relax and embrace it to get good effects. Peoples reactions to drugs vary, one reason that seems somewhat likely to me is perhaps people who metabolise less codeine into morphine get the stimulating effects.
You really need a few tries to appreciate codeine fully I think, misk if I were you I would try a higher dose but parhaps keep an antihistamine on hand. I have to say I think codeine is one of the most under rated drugs ever, I have done most commonly available opiates but codeine just hits the right spot for me tolerance permitting.
Sorry I ended up rambling a bit, had a few bourbons and a nice CWE and got carried away lol
