Are you afraid that the milk wont go through the teat hole?
then I doubt that the bottle would make a difference but then if you made the teat-hole bigger you'd probably interfere with the whole 'anti-colic' mechanism in the bottle
have you tried the 'nuk' bottle, they have a teat (size 3 bottle I think) that can easily let down thicker milks. My son had refulx and was on a formula with a thickener added and they done the trick for us.