I got caught up in the great Mt. Washington Pad Panic of '01. As some may remember, the Mt. Washington was the predecessor of the Nitelite. My experience with that pad mirrors that of several of the hikers in this post. Bumpy side down, use in combination with a thinner closed-cell pad, and careful site selection all help.
But I often sleep in high and rocky places where soft ground is difficult if not impossible to find. As a side sleeper, I could seldom get a good nights' sleep.
Later I tried the Tylenol PM idea and it worked to some extent. But it occurred to me that I could go even lighter by bringing an UL hypodermic needle and shooting up. Then, no pad would be required. Though I would be sleeping in the dirt, I really wouldn't care.
Ultimately, though, I just gave up on the Mt. Waahington and now get a good night's sleep with a Monbell 90 + 1/4" thinlite. Weight is 12 oz.