For the most part, it has little to do with size, and more to do with your personality, how fun your shows are, etc. I'm a size 20 with a 36K rack - so I get guys who are really into boobs, butts, hips, as well as those like bellies - though that is probably the only thing that makes me uncomfortable. I've had high room counts, low room counts, made 337 tokens in an hour in a half, made 5 tokens in three hours. However, I'm working camming in around a 40-hour/week office job, so my cam schedule is highly inconsistent. If you want to try just selling videos, Clips4Sale has a very successful BBW category, and the first video I sold was me weighing and measuring myself to show the guys how big I am.
I get occasional haters, a guy passing through making a "whale" comment on occasion, but every girl gets some kind of insult - they'll insult thin girls because "I don't like seeing ribs", hair color, eye color, wearing glasses, not wearing glasses, having tattoos/body piercings, not having tattoos/body piercings, being "too tan", being "too pale".
Insulting people for things they can't control baffles me. Just.... Why? Do they have nothing better to do? My viewpoint is that every body type is beautiful if you're happy and healthy.
I created an account to cam with a friend who is a size 3. She's gorgeous. I was telling my regulars about our new account and when we'd be on, and one of them said that he doesn't like anyone smaller than a size 14. Because men actually know what women's clothing sizes mean and can say, "Oh, ew, she's a 12, she's too skinny for me" just by seeing someone on the internet. We never actually got around to camming on that account, but we've cammed on a couple sites (don't remember what they are), and we'd have people who like both of us - who doesn't like seeing two topless ladies? - or people who would hate on one or the other. We'd just ignore them, or ban them if they were being real assholes.