Hi Joe
Done a mock up so hope this helps and you can follow.
1st i cut 4 strips of wine bottle top
I then cut ahort pieces off 2 strips the black ones
Next i glue the 2 silver ones at a slight angle
These make up the back of the harness.
Next the long black ones are the front of the harness that run feom the securing point on the frame behind the seat.
Glue the 2 short black strips to the main straps
Then glue the back and feont [silver and black] together.
Mind you need a fair bit of strap to reach the frame behind the seat
Next i cut really small strips to run across the straps where they join the small bits. Simulating the buckles.
Also poke 3 holes down the bottom of the front straps.
Lastly a small strip for the crotch strap.
Just a simple copy of the harness but looks okay once its in place. I painted mine buff.
If you are building a smaller scale than 1/32 which mine is, you could miss out the back straps and buckles.
Good luck Joe.
Pete