I have been considering a rail such as the OP's. On that bolts to the topside or bottomside of the handguard. I want a flashlight and possibly the angled grip by mqgpul. Do the little rails hold up well? Also, it looks like something would be easy to break when using a grip, whether it be part of the rail or handguard. One last concern, wouldn't plugging the holes with bolts cause an extra buildup of heat