Okay, I'm a little confused. I'm looking to get a 100% natural talalay mattress topper, but when I look into Latex International, even their site says they use a mix of natural latex and Polystyrene-butadiene Rubber Latex (which is derived from petrochemicals). Is a 100% natural product available? Also, your site just lists soft, medium and firm and not the ILD rating on each. Are there ILD ratings?