Thanks Valor, the tape wouldn't arrive from Amazon to Australia in time for me, so I guess, I will try the tape I purchased and see how it goes, and order the 3M tape for a backup.
The part I am confused by, is do you jbweld the t-nuts directly to the shield, drill a hole in the large brackets, and then tape the large brackets to the shield directly, with the t-nuts poking through the hole in the brackets. Then attach the small pentagon brackets with bolts, so that they stand-off from the large brackets?
I guess once he belts are on, I will be able to see how to mount the shield on your back, at the moment, it just won't click for me, too many late nights I guess!
Thanks everyone for the help, I am enjoying the challenge so far.