Snorting - heroin

[cobetcknncoio3]

SWIM has just gotten a half-gram of heroin. SWIM has never tried it before, and after plenty of research, has ruled out smoking (not a strong enough effect) and injecting (too nasty/dangerous/intense), and will insufflate the powder. i read on another website that an average dose for a first-time heroin user who is snorting, is 5 to 10 milligrams. SWIM has a total of a half-gram (500 milligrams) and so, obviously, the line would be very, very small, since only a small amount would be needed. the only other drug SWIM has snorted is amphetamine (finely ground adderall), and the 50mg that SWIM snorted of that made about 9 lines, and burned like hell. obviously, snorting heroin would be a lot different. how does SWIM lay a line of heroin so that it's not too small and won't have the full effect, but also not too large and will make SWIM overdose? apparently, if a regular first-time dose is 5-10mg, then if SWIM were to divide the half-gram into 10mg lines, he would get a total of 50 lines how long and how wide would each 10mg line be?

thanks, sorry for the long post, but SWIM just wants to try heroin for the first time without overdosing!