I also installed Magpul XTM panels on the side & bottom rails. I put 2 panels on coming from the back end on each which give you a good hand-hold position. I put ladder rail protectors on the remaining front portions of the side & bottom rails (except for the left with the CQD sling mount) for other attachments like a light mount & vert grip.

The XTM's barely snap shut on the rails and are tight. The rails must be at the upper end of the Picatinney specs.

My .02