If you're looking for a "boot" style pad, I've had great luck with one by Beartooth Products. It comes in a brown that seems to blend with most stocks but more importantly consists of a very light, thin and stretchable rubberlike outer sheath that has different thickness inserts thus allowing you to get the right combination needed. It doesn't add any real weight to the gun and has the added advantage that it's so easy to install you'll find you remove it when not in the field so your gun doesn't look ugly. I've never liked the lace-on pads looks or weight but this one's pretty neat. The only thing I've had any problem with is that above about 1/2" thickness addition, they seem to be a little "loosey-goosey" sideways but you said you needed 1/2" so it's worth a try. Their site is
www.beartoothproducts.com and I think you'll be pleased. Good shooting...