Boss construction

[Jack Vellum]

You need to bend the plate to the curve first, then make a curved former with the boss hole cut in. I would make the former as robust as you can to get the job done and help to support the metal for him. I would say this would be easier to do than trying to do it flat    I use a metal flat former but use a heavier gauge plate.

The bosses on some of the shields of the RMRS ( from RMRS website gallery ) I made years ago on a flat former.
Still hat of to a budding armourer   good luck.
Regards Brennivs

Thanks, 
Just had a brain wave after reading this. I got him to do a trial run with the ply off cuts (they were about 150mm to short for a second scutum) It just so happens it has the right curve for a curved former.