I got the 1,450 lumen Olight Sigurd (240 meter throw) mounted on the 16" AR today on a 13-slot Picatinny rail on the bottom of the handguard. The Pic rail is aluminum, hollowed out on the back to save weight, and takes up 3 slots. I put a half-slot piece of Magpul rail cover behind it. I already took the Olight 800-lumen PL Turbo Tactical Light with Spotlight and Floodlight (515 meter throw) off the VRF14 and put it on my Remington shotgun, and I put the 1,000 lumens PL-3S Valkyrie Rail Mount Light (200 meter throw) that was on the left side of my 12.7" AR on my VRF14. I put the 1,350 lumen Baldr Pro Tactical Light & Green Laser (260 meter throw) on the bayonet lug mount on the 12.7" AR instead. I gave the elevation on the laser a turn and have it somewhere near parallel. I'll have to wait until I fix my vise to adjust it better. My vise is in pieces after trying to bend a couple pieces of steel that didn't want to bend any more. Not even with a sledgehammer, hence the broken vise (and workbench in need of repair).
Now there's nothing on the FSB mount, and I can use the QD sling port on either side.
I have the 2 highest lumen lights on the rifles and the 2 lowest on the shotguns. I still have the 1,000 lumen Streamlight ProTac Rail Mount HL-X weapon-mounted light (447 meter throw) on my MechTech CCU, and may not put a light on the 20" AR at all. I don't plan on carrying a 20" rifle with a scope and bipod at night when I have a 16" upper with a light on it. I used a Sharpie to black out all the markings on the PL Turbo, PL-3S Valkyrie, and Baldr Pro, except for the 3-way switch markings on the Baldr Pro that tells you laser, laser + light, and light. The Sigurd is already completely black, except for some markings on the bottom of the head, and they make a Desert Tan model that's completely tan except for the same markings. I blacked mine out with a Sharpie. The PL Turbo and PL-3S Valkyrie are both 1.44" wide and have 2 Olight 1600 mAh CR123A non-rechargeable lithium batteries. But the PL Turbo is .39" longer, and .08" taller, and .28 ounces heavier than the the PL-3S Valkyrie. They look nearly identical, except for the longer head on the PL Turbo. I have some spare Olight batteries but bought a dozen spare 1,550 mAh SureFire lithium 123A batteries too. They have a 10-year shelf life.
https://www.olightstore.com/sigurd-angled-grip-light https://www.olightstore.com/baldr-pro https://www.olightstore.com/pl-3s-valkyrie-rail-mount-light https://www.olightstore.com/pl-turbo-tactical-flashlight-with-spotlight-and-floodlight https://www.surefire.com/123a-batteries/?sku=SF12-BB