On my carbine here I'm mainly using Magpul Enhanced XTM rail panels on the sides, XTM Hand Stop kit at the bottom and LaRue Index Clips at the top rail.
Before I used the LaRue Indes Clips I was just either using some XTM panels with small gaps between the panels or Magpul ladder covers.
Ladder covers protects hands, gloves and gear from the sharp picatinny rails but it have no heat and impact protection, then I tried XTM panels on top but kind of bulky, finally the Index Clips is a good compromise of less bulk and rail protection.
My only slight drawback with the XTM panels is when I want to use my QD vertical forward grip it is slower to remove the panel by using two bullet tips or tools.
If I plan on using my vertical forward grip ahead of time I usually remove the bottom front XTM panel and use my short panel Knight's Armament or TangoDown which could be removed quickly by unlocking the front end.
I also used Knight's Armament, ProMag and TangoDown different lengths of rail covers but it made the rails felt wider, and their fit on the rails varies some are snug and some have a little movement.