I'm bigger and have no problem getting clients. You just have to market right. TERB is not a place to be asking this. Most that are vocal on here are going to say what they are saying.
The non-vocal ones are the ones who book.
Why? Because the non-vocal ones fear being chewed out and rightly so. Too many here would say "why pay for a fattie when you get that for free" That is the mentality of most of the vocal posters. Again, as you can see here.
The key to this business is finding your spot in it. Market to the right clients, place you rate for that clientele in combination for what quota you need to make taking into account expense and update! Update, update, update! You need a reason for men to keep coming back to your site, ads, twitter, etc. Not just coming back to your bed.
Lastly, as stated, sex appeal will attract almost any man to any size woman. Period. Men are driven by sex, if you have no sex appeal, you are going to have difficulty at any size.