You know, I really wouldn't bother with the whole grapefruit juice, turmeric, and other potentiators. I've never really noticed any difference in terms of effects from taking them. I know some people will swear by it and I guess it probably has to do with individual brain chemistry, but I would first just try kratom by itself. I've never gotten leaf, just powder, from what I've read it's easier to deal with especially if you're making tea, and it probably absorbs faster. The only thing that I've heard that everyone seems to agree with is that kava and kratom have a really great synergy which I'd like to try.
If you're switching from opiates, IMO of the strains I've tried, Bali is the most traditional in terms of 'opioid' effects and sedation. It's kind of nice to have a few strands on hand to keep things fresh, but IME (which is limited to only a couple months now of using kratom in place of Buprenorphine), it's more important to just get good kratom, rather then strand, because after a while it all really does the same thing, as long as it's good. The only times I can notice a difference is if one strand is especially weak seeming, or if I just use one or two strands for a couple of weeks and then get a new one. The white vein maeng da is pretty good for it's stimulating properties, but at the right dosage it can be sedating too.
Also be careful not to dose to high on kratom, I made that mistake when I first started taking it, thinking that 'well if 7g has me feeling great, then 21g will have me nodding!'. Kratom does not work like that, and a kratom overdose is a very unpleasant think-feels kind of like experiencing a caffeine overdose while high and paranoid on marijuana, and it makes you dizzy, nauseous and shaky. It sucks. After a while I've become more tolerant to kratom so I can handle slightly higher dosages, but it seems there's really no use for me to take more then 6-7g (via the T&W method). With lower dosages I really believe you can enjoy it more, but it's the kind of thing you've got to experiment with. I still fuck up and try to get high off of it more often then I'd like, and I'm always underwhelmed. So I'm learning to be happy with what I do get from it, and it's a hell of a lot better then suboxone, IMO.