O-ring considerations

[asgeirtj]

I use these

http://www.theoringstore.com/index.php?main_page=product_info&products_id=1774

on my cherry profile caps.  1mm is just perfect for me, it shortens the travel distance just a tad and removes the bottoming out sound. However the landing is quite harsh, I was wondering if there was 1mm o-rings to be found somewhere which are softer?