Just read your post Randy, maybe I can be of help. I build scratch boxes for several customers up in GA. and they seem to like them, so here goes. I looked at the link given to you by SpitnDrum and the builder there uses a box similar to the one I build with some differences. The resonator plate he uses on his box seems to be somewhat thicker than mine and also his does not extend beyond the edge of the box. I use a plate about 1/16 of an inch thick, also of cedar, but mine extends beyond the edge of the box about 1/4 inch. I taper the extended portion of the plate carefully as well as rounding the edge while tuning the box to get the sound I like. I use a turned cedar "striker" about 5/16 to 3/8 inch in diameter about 2 1/2 inches long(I turn them myself). I use box chalk on the "striker" just as you would on the lid of a box call. The mouth opening shown on the call in the link appears to be about 1/16 inch that's pretty much the same as mine.
To work the call you can either hold the "striker" steady between the thumb and forefinger of your left hand and the box between the thumb and middle finger of your right, resting your index finger on the bottom of the box. The box will be upside down with the resonator plate facing away from your right palm, by using a rocking motion you can then work the edge of the lip on the "striker". You can also hold the box steady and work the lip with the "striker" holding everything right side up.With practice you can make yelps, clucks and purrs. Like a pot call scratch boxes work well for subtle close in work. Hope I did not confuse you and that this will help.
No matter what design you use a scratch box will add a lot to your calling.
Handcrafted Turkey Calls