I have to say that the key is patience and it works in more ways than one.
First - when you find a woman interested in you and then she balks at sex because of your size, I have found that this is definitely not the final word on the subject. Just seeing your size will work on her curiosity. It may be a day, a week, a month or longer but there is a good chance that her curiosity will bring her back, sometimes just to reaffirm that she saw what she saw and then you go from there.
Second - once she decides that she wants to give you a try, often "just for fun", I usually encourage her by letting her be on top. This lets her have control so she takes what she can handle at her own pace. Be patient. I also let her know that "no one says you HAVE to take it all" but I find that when they have control of things women do try to see how much they can take and the more fun for them then the more they will return "just to see" if they can handle more.
Third - whether its home renovations, picking furniture or clothes for their wardrobe, women like projects. If you are lucky enough to become a project (ie- "I want to take it all"). You can help with suggestions of lube or "toys" that will speed the process. Being helpful in such ways only works once the woman has decided that this is something they want.
Fourth - women do seem to "tell tales" and it may take some time but again, be patient, women's curiosty is often a good thing and they have excellent memories. What they have heard about you will be passed around somewhat discretely and those that hear will put it down to memory for verification at what they think is an appropriate time (ie - if you break up with their friend or they break up with their boyfriend)
I guess all in all I'd have to say "time is on your side". Patience is a virtue.