Chain guard holder on the swing arm gone

Hello all,
On my 72 Norton the chain guard holder (horse shoe shape thingy ) on the swing arm was gone when I bought the bike. Im going to get it repaired then painted. But I don't know its dimensions. Does anyone know? As I will need to give this to the engineer to repair/weld.

Thanks Bryan

I made the piece your talking about and never mounted it. The swing arm was the unbraced type and was bent bad just bought a new arm. It was an easy fab but I did have a god sample at the time.

Brian
I have mine apart for a 520 chain mod so this is what I measured. The loop was replaced a while back so can't guarantee it's original size but measures 32,0 wide x 22,0 high and is in 1,2 guage steel. The loop ID is 10,0. Hope that helps.