hi again, i weigh about the same as you and am about the same height, i was on 40mg a day for 4 months. to tell you the truth my acne was only mild but my skin was super oily, i took it because i was 23 and had had this problem since i was 11, had tried everything under the sun (diet, over the counter products, antibiotics, the lot!) and had just about had enough!
i got a really really minor break out in the 2nd week on accutane. but i had just stopped minocycline antibiotic so im not sure if it was down to that. either way i was just glad to be on accutane so i didnt care too much. i was then pretty much clear from week 3 onwards, every week was different though, one week id be totally clear, the next 2-3 spots would appear. by the end i was totally clear. don't get disheartened if you're still breaking out months into treatment, for some people it doesn't work til after treatment.
side effects wise, the usual ridiculously dry lips/arms (lip balm and eucerin/baby oil helped that) i got bad body aches in the 1st month, but i think my job contributed to a lot of that- i have to sit all day leaning over my patients so by the evening it got bad! ibuprofen was a god send for that. other than that it was fine.
any more questions let me know.