I agree with nikko that I have no knoweldge about this topic. But, as far as guaranteeing yourself a C-section I don;t think there is a way to do that without talking to your OB. If you let him/her know how you are feeling and what your GP said, the OB will let you know the best course of action. Good luck!
I must say, I'm just not sure about this. Have you tried posting in the 18-34 pregnancy forum, maybe someone there will be able to help since they have a broader number of women in that forum. I had no idea that varicose veins could get so bad nor that they could be in the nether regions. Pretty much that is what a hemeroid is so, I guess it would make sense that you could get one there too. Be sure to discuss with your OB, I'm sure things will work out so that the best option is chosen for both you and baby.