I use a Kifaru 26" frame. 6'1" 220. Thin muscular build.
Start at belt, cinch down, adjust shoulders until they fully wrap shoulders, there should be a gap between the shoulder blades and pack, tighten load lifters until pack touches back, tighten chest straps to keep them from moving.
People's belly buttons are not all in the same place. A better reference is the illiac crest.
The iliac crest is the curved part at the top of the hip. It forms the wing-like part of the pelvis on which a person will sometimes rest their hands.
Sent from my SM-S918U using Tapatalk