I am looking into buying a Mirage G4 from a 5 9" 190 lb guy. Im 6 ft and 170. When I put the rig on the leg straps are fine but there is a lot of lift on the bag when pulled up. What straps mainly cause this? Also, which strap is the MLW and which is the lateral? Sorry Im a newbie and am trying to understand all of this. Thanks,