50mg is a huge dose for a beginner not necessarily because they will get high as hell (they probably will) but because Adderall has some horrendous side effects when compared to meth.
A newbie might end up with stomach cramps, nausea, racing heartbeat, feeling faint, etc if they take too much Adderall. When I had no tolerance, 50mg was very uncomfortable; I about had an anxiety attack, had a splitting headache, and a pale face with bluish lips.
30mg was plenty when I didn't have a tolerance, and higher doses didn't really give a better buzz, just more edginess. I would reccomend you take it orally but you can snort some and swallow some if you are impatient. Just don't snort your entire dose because you might be disappointed. Of course you can move on to 50mg if 30mg doesn't work for you, but I would err on the side of taking too little the first time instead of too much.