8 & 12 MG are low, but the reason you want low is because it is condensed. You could get one hit that is a monster, and the rest all weak. Matter of fact, I have some Tangiers that doesn't wanna acclimate 100% to my liking, so i added some blueberry to it. I added 7 drops or so, but my level is 18MG. Standard is about 15-18. My understanding is that shiazo stones are very similiar to e-cigs. I vape alot [e-cigs...] and they are entirely made up of
2: Base (PG/Propylene Glycol OR VG/Vegetable Glycerin) <--- Also makes smoke/vapor
So what i would do, is get some USP grade Vegetable Glycerin (google search "e-liquid + vegetable glycerin + sale")
and mix it w/flavoring, (again only use e-liquid/e-cigarette stuff cause' you know it's safe to inhale) and nicotine juice. You can use a calculator from [url="http://www.ejuice.breaktru.com/"]http://www.ejuice.breaktru.com/[/url] if you want one that is downloadable, or online @: [url="http://www.todmuller.com/ejuice/ejuice.php"]http://www.todmuller.com/ejuice/ejuice.php[/url] this way you never have to buy the shiazo liquid again. Thing to keep in mind, because of the amount you will be smoking- instead of using the normal 15% flavoring, 15% nicotine, the rest VG OR PG (Though i recommend VG! It's in almost all shisha, that and honey); i would use like 5% nicotine. You might think, oh well i already have this juice... Well, that's true. But you need at the minimum a good amount of liquid to absorb the nicotine evenly. And really, I make all my own e-liquid, and it costs me about $0.15/pack. And BTW: in those cartridges, it is equal to the amount of 2 packs of cigarettes, though not really because all the additives and gun powder etc in cigarettes help your body absorb the poisons better. So you feel less nicotine essentially. I tried adding juice to my bowl right now and i got a few big big hits, and i'm sure the rest randomly burned away... lol. So, my point is that it just must be spaced out and mixed really well. Good luck, if you get stuck pm me or have the admin shoot me an email.
PS: I didn't list the actual vendors i buy from because I don't want to promote anything, just show you the correct route from an experienced user in both fields. The above links are all free.