...and order a set of pads for the upper straps. Your passengers will like you for it and it allows the harnesses to be made
TIGHT. You don't want the torso to have slack in the belts-only arm movement. Keeps you in the sea better too.
Oh and if you switch to eyebolts in the bulkhead and floor, with clips on the belts, it's cake to snap them in and out for maintenance or work.