My $0.02 in terms of using the NICE and guidelight frames, their published sizes are too large for a heavy load in the pack. They seem fine at typical backpacking loads but not meat hauling, for instance I'm a 34" waist and I bottom out their 29-34" belt if I have a load over 90lb. My 31" waist buddy can't use a 29-34" belt past like 40lb or it just slips. No experience with the guidelight MT frame.