How about a black leather US shoulder holster? Military issue, complete and mint. You won't have to make one, just adjust this one to fit.
$30 shipped to your door.
It has plenty of adjustment and an extra chest strap that adjusts. Should work, but I'll leave it up to you.
It's MILSPEC issue I'm sure you've seen them.
that's it exactly. WWII was the M-5. this is the M-7, the only difference is an additional chest strap. the chest strap is optional (on or off) and it doesn't affect the looks of the rig.
I am selling mine. It is like new and made by Adirondack Leather company. I am asking $35 by Paypal and FREE shipping if you are interested. It has the NATO serial Number on the back .
I am a big guy too and I replaced the leather shoulder strap on my M-7 with a USGI OD General Purpose strap. Much more comfortable and plenty of adjustment.
Hope that helps!