I would not fixate overly on the touching of the top edge of the plate. However, if you finger tip is five inches from the plate top edge, either you have short arms or a range of motion issue or it is way too low such that it is down on your butt. At 5'9" there is just not enough of you to have a standard plate five inches low! So I am skeptical of this.
As happy-diver says, with some loose interpretation
, a wrist is not a fist. My fist easily, with no force, can sit between my shoulder strap and me. It is the waist strap that stabilizes the rig, it should be snug, the crotch and shoulder straps just provide limits (IMO). Your straps may seem a little loose to me actually. But a wrist is not a fist
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Getting in and out on deck with rig in rack, splay the shoulder straps out, flip the waist straps outward, lay the crotch strap down centered. Standing, place arms at side, flip wrists and hands out and sit down into the harness. Flip the shoulder straps over your shoulder, stand up and get the rest situated and connected. Getting out, same thing, open the waist and crotch while standing, sit down with tank going into rack, put arms at side, stand up. No chicken winging required.
As happy-diver says, with some loose interpretation


Getting in and out on deck with rig in rack, splay the shoulder straps out, flip the waist straps outward, lay the crotch strap down centered. Standing, place arms at side, flip wrists and hands out and sit down into the harness. Flip the shoulder straps over your shoulder, stand up and get the rest situated and connected. Getting out, same thing, open the waist and crotch while standing, sit down with tank going into rack, put arms at side, stand up. No chicken winging required.