Looking forward to learning something I didn't know about goose calls and long reed setups! I can't even begin to picture a 4 piece reed/toneboard setup so I'm definitely curious!
Basic long-reed goose call toneboard and wedge, also commonly called a conventional goose call.
I usually make a few of these yearly. The custom milled 1/2" toneboards are ran through a shaper using a 3-wing 1/4" cutter. A four piece set-up can consist of a thin wall .500 brass tube recessed into goose insert to prevent split out or in this case a friction fit toneboard, wedge, mylar reed with a
o-ring set-up. I also use 1/2" retainer rings in some cases to prevent wedge misaligment.
Here's a custom Koa Classic model showing the gut set-up.