Well, I've just purchased the shoestring shaders from DAZ 3D and never got a password, so it's only working in evaluation mode at the moment. Therefore a large black rectangle is on my glass, but if you can disregard that this image shows the fresnel effect for glass. I added the shoestring fresnel to the refraction part of the shader tree by the way (I hope that's right). Still too much refraction in my opinion but there are a lot more parameters to fiddle with now.