truck camper question

I have the rails in my truck bed. I have tried most methods to raise the TC over the rails. I have several several different platforms, used platforms with rubber mat, used 4x4, used 2x6 (laid flat), and used ridged foam. Of all the methods I have used, I prefer the 2x6 (kiln dried for lighter weight) laid flat, and that is what I am using now. Relatively light for me to load and unload and do not compress at the edges of the TC.

Wayne