I have a modified SUPAIR PPG harness but wanted ore comfort and butt protection so, I grabbed an older 17cm BUMPAIR and pushed it between te frame and the harness. The advantages are:
1 / it pushes the lower section of the harness away from the mid-section of the frame and brings a more ergonomic shape to the whole thing. Since the human spin is curved, it becomes a more natural/comfortable way of sitting. I always fly with a foot-rest for added comfort and it really feels like being in a lounge chair - legs extended with the knees slightly bent and the backrest curved.
The carrier was salvaged from my neighbor’s curb trash - I ran down the driveway and grabbed it just before the recycling city truck was making its way up to my place😄 After a few cuts here and there, a small carpeted mat, a piece of 1/2" treated wood, two kitchen closet handles strategically localed to balance the platform weight during installation (makes thing way more easier to connect int to hitch receiver and remove), I drilled another hole closer to the platform for a more compact design, I used an old OXO kitchen vegetable cutting board to mount the car’s license plate, attached a bicycle rechargeable light with all kind of modes to it - the light can be recharge on the cigarette lighter (I have two lights), 3 tie-downs and I was all set. I keep the X4 in one piece. The whole thing is rock solid at 65mph on the highway. I made four dust covers for the four motors and secured the blades with 6" bungee-balls, otherwise they will start spinning at around 35mph. I drove back in sustained rain this morning, then the skies cleared out, and by the time I was back home, all was dry and just fine. All good!