So I've had a set of Halos for about a year. Love the light weight and no clamping but I eventully realized that there was little or no noise attenuation using any of the supplied ear tips. Read up on fitting tips but still no luck.
I tried some foam plugs as described in this thread and some were not too bad.
Then I discovered Westone TRUE-Fit ear tips. I purchased an assortment and found a size I thought worked. When I tried them in the plane there was still a lot of noise. Went up a couple of sizes and finally got a great fit. The noise is gone. Just as good as the custom molded earpiece I had on my old Panter headset. Here is a link to Westone.
http://www.westoneaudio.com/index.php/products/tips/true-fit-tips.html
I purchased my tips from here
http://www.earplugstore.com/westone-truefit-tips-pair.html
Jim Butcher