i have found a cheap rail cover in para cord. It might not look like it, but it is quite smooth and slick, but still give you good grip with or without gloves. also, it is wrapped really tight so that the cord spanning between the rails has very little play at all. i used a short dowel and wrapped the free end around it to help pull really tight.
i just started in one rails 'valley' and continiously went down to the next 'valley' until i reached the end and then went back up. if that doesnt make sense I can post a diagram or video.
you can skip over areas you want to attach stuff to (forward grip, bipod, ect.).
plus, you will always have emergency cord with you for whatever.
just a thought. obviously not for everyone.